Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems:

Seth Jenkins discovered that the Linux kernel did not properly perform address randomization for a per-cpu memory management structure. A local attacker could use this to expose sensitive information (kernel memory) or in conjunction with another kernel vulnerability. (CVE-2023-0597) It was discovered that the IPv6 implementation in the Linux kernel contained a high rate of hash collisions in connection lookup table. A remote attacker could use this to cause a denial of service (excessive CPU consumption). (CVE-2023-1206) Yu Hao and Weiteng Chen discovered that the Bluetooth HCI UART driver in the Linux kernel contained a race condition, leading to a null pointer dereference vulnerability. A local attacker could use this to cause a denial of service (system crash). (CVE-2023-31083) Ross Lagerwall discovered that the Xen netback backend driver in the Linux kernel did not properly handle certain unusual packets from a paravirtualized network frontend, leading to a buffer overflow. An attacker in a guest VM could use this to cause a denial of service (host system crash) or possibly execute arbitrary code. (CVE-2023-34319) Lin Ma discovered that the Netlink Transformation (XFRM) subsystem in the Linux kernel contained a null pointer dereference vulnerability in some situations. A local privileged attacker could use this to cause a denial of service (system crash). (CVE-2023-3772) Kyle Zeng discovered that the networking stack implementation in the Linux kernel did not properly validate skb object size in certain conditions. An attacker could use this cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2023-42752) Kyle Zeng discovered that the netfiler subsystem in the Linux kernel did not properly calculate array offsets, leading to a out-of-bounds write vulnerability. A local user could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2023-42753) Kyle Zeng discovered that the IPv4 Resource Reservation Protocol (RSVP) classifier implementation in the Linux kernel contained an out-of-bounds read vulnerability. A local attacker could use this to cause a denial of service (system crash). Please note that kernel packet classifier support for RSVP has been removed to resolve this vulnerability. (CVE-2023-42755) Bing-Jhong Billy Jheng discovered that the Unix domain socket implementation in the Linux kernel contained a race condition in certain situations, leading to a use-after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2023-4622) Budimir Markovic discovered that the qdisc implementation in the Linux kernel did not properly validate inner classes, leading to a use-after-free vulnerability. A local user could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2023-4623) Alex Birnberg discovered that the netfilter subsystem in the Linux kernel did not properly validate register length, leading to an out-of- bounds write vulnerability. A local attacker could possibly use this to cause a denial of service (system crash). (CVE-2023-4881) It was discovered that the Quick Fair Queueing scheduler implementation in the Linux kernel did not properly handle network packets in certain conditions, leading to a use after free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2023-4921)

It was discovered that the KVM VMX implementation in the Linux kernel did not properly handle indirect branch prediction isolation between L1 and L2 VMs. An attacker in a guest VM could use this to expose sensitive information from the host OS or other guest VMs. (CVE-2022-2196) It was discovered that a race condition existed in the Xen network backend driver in the Linux kernel when handling dropped packets in certain circumstances. An attacker could use this to cause a denial of service (kernel deadlock). (CVE-2022-42328, CVE-2022-42329) Gerald Lee discovered that the USB Gadget file system implementation in the Linux kernel contained a race condition, leading to a use-after-free vulnerability in some situations. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2022-4382) José Oliveira and Rodrigo Branco discovered that the prctl syscall implementation in the Linux kernel did not properly protect against indirect branch prediction attacks in some situations. A local attacker could possibly use this to expose sensitive information. (CVE-2023-0045) It was discovered that a use-after-free vulnerability existed in the Advanced Linux Sound Architecture (ALSA) subsystem. A local attacker could use this to cause a denial of service (system crash). (CVE-2023-0266) It was discovered that the iouring subsystem in the Linux kernel contained a use-after-free vulnerability. A local attacker could possibly use this to cause a denial of service (system crash) or execute arbitrary code. (CVE-2023-0469) It was discovered that the CIFS network file system implementation in the Linux kernel contained a user-after-free vulnerability. A local attacker could possibly use this to cause a denial of service (system crash) or execute arbitrary code. (CVE-2023-1195) It was discovered that the RNDIS USB driver in the Linux kernel contained an integer overflow vulnerability. A local attacker with physical access could plug in a malicious USB device to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2023-23559)

It was discovered that the Packet network protocol implementation in the Linux kernel contained a double-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-22600) Jann Horn discovered a race condition in the Unix domain socket implementation in the Linux kernel that could result in a read-after-free. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-4083) Kirill Tkhai discovered that the XFS file system implementation in the Linux kernel did not calculate size correctly when pre-allocating space in some situations. A local attacker could use this to expose sensitive information. (CVE-2021-4155) Sushma Venkatesh Reddy discovered that the Intel i915 graphics driver in the Linux kernel did not perform a GPU TLB flush in some situations. A local attacker could use this to cause a denial of service or possibly execute arbitrary code. (CVE-2022-0330) It was discovered that the VMware Virtual GPU driver in the Linux kernel did not properly handle certain failure conditions, leading to a stale entry in the file descriptor table. A local attacker could use this to expose sensitive information or possibly gain administrative privileges. (CVE-2022-22942)

USN-4303-1 fixed vulnerabilities in the Linux kernel for Ubuntu 16.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 16.04 LTS for Ubuntu 14.04 ESM. Paulo Bonzini discovered that the KVM hypervisor implementation in the Linux kernel could improperly let a nested (level 2) guest access the resources of a parent (level 1) guest in certain situations. An attacker could use this to expose sensitive information.

USN-4255-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu 16.04 LTS. It was discovered that the Linux kernel did not properly clear data structures on context switches for certain Intel graphics processors. A local attacker could use this to expose sensitive information. (CVE-2019-14615) It was discovered that a race condition can lead to a use-after-free while destroying GEM contexts in the i915 driver for the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2020-7053)

USN-4253-1 fixed vulnerabilities in the Linux kernel for Ubuntu 19.10. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 19.10 for Ubuntu 18.04 LTS. It was discovered that the Linux kernel did not properly clear data structures on context switches for certain Intel graphics processors. A local attacker could use this to expose sensitive information.

USN-4068-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.04 for Ubuntu 16.04 LTS. Adam Zabrocki discovered that the Intel i915 kernel mode graphics driver in the Linux kernel did not properly restrict mmap() ranges in some situations. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2019-11085) It was discovered that a race condition leading to a use-after-free existed in the Reliable Datagram Sockets (RDS) protocol implementation in the Linux kernel. The RDS protocol is disabled via blocklist by default in Ubuntu. If enabled, a local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2019-11815) It was discovered that the ext4 file system implementation in the Linux kernel did not properly zero out memory in some situations. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2019-11833) It was discovered that the Bluetooth Human Interface Device Protocol (HIDP) implementation in the Linux kernel did not properly verify strings were NULL terminated in certain situations. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2019-11884)

USN-4006-1 fixed a vulnerability in the Linux kernel for Ubuntu 18.10. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.10 for Ubuntu 18.04 LTS. Federico Manuel Bento discovered that the Linux kernel did not properly apply Address Space Layout Randomization (ASLR) in some situations for setuid a.out binaries. A local attacker could use this to improve the chances of exploiting an existing vulnerability in a setuid a.out binary. As a hardening measure, this update disables a.out support.

USN-3981-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu 16.04 LTS and for the Linux Azure kernel for Ubuntu 14.04 LTS. Ke Sun, Henrique Kawakami, Kekai Hu, Rodrigo Branco, Giorgi Maisuradze, Dan Horea Lutas, Andrei Lutas, Volodymyr Pikhur, Stephan van Schaik, Alyssa Milburn, Sebastian Österlund, Pietro Frigo, Kaveh Razavi, Herbert Bos, Cristiano Giuffrida, Moritz Lipp, Michael Schwarz, and Daniel Gruss discovered that memory previously stored in microarchitectural fill buffers of an Intel CPU core may be exposed to a malicious process that is executing on the same CPU core. A local attacker could use this to expose sensitive information. (CVE-2018-12130) Brandon Falk, Ke Sun, Henrique Kawakami, Kekai Hu, Rodrigo Branco, Stephan van Schaik, Alyssa Milburn, Sebastian Österlund, Pietro Frigo, Kaveh Razavi, Herbert Bos, and Cristiano Giuffrida discovered that memory previously stored in microarchitectural load ports of an Intel CPU core may be exposed to a malicious process that is executing on the same CPU core. A local attacker could use this to expose sensitive information. (CVE-2018-12127) Ke Sun, Henrique Kawakami, Kekai Hu, Rodrigo Branco, Marina Minkin, Daniel Moghimi, Moritz Lipp, Michael Schwarz, Jo Van Bulck, Daniel Genkin, Daniel Gruss, Berk Sunar, Frank Piessens, and Yuval Yarom discovered that memory previously stored in microarchitectural store buffers of an Intel CPU core may be exposed to a malicious process that is executing on the same CPU core. A local attacker could use this to expose sensitive information. (CVE-2018-12126) Vasily Averin and Evgenii Shatokhin discovered that a use-after-free vulnerability existed in the NFS41+ subsystem when multiple network namespaces are in use. A local attacker in a container could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-16884) Ke Sun, Henrique Kawakami, Kekai Hu, Rodrigo Branco, Volodrmyr Pikhur, Moritz Lipp, Michael Schwarz, Daniel Gruss, Stephan van Schaik, Alyssa Milburn, Sebastian Österlund, Pietro Frigo, Kaveh Razavi, Herbert Bos, and Cristiano Giuffrida discovered that uncacheable memory previously stored in microarchitectural buffers of an Intel CPU core may be exposed to a malicious process that is executing on the same CPU core. A local attacker could use this to expose sensitive information. (CVE-2019-11091) Matteo Croce, Natale Vinto, and Andrea Spagnolo discovered that the cgroups subsystem of the Linux kernel did not properly account for SCTP socket buffers. A local attacker could use this to cause a denial of service (system crash). (CVE-2019-3874) Alex Williamson discovered that the vfio subsystem of the Linux kernel did not properly limit DMA mappings. A local attacker could use this to cause a denial of service (memory exhaustion). (CVE-2019-3882) Hugues Anguelkov discovered that the Broadcom Wifi driver in the Linux kernel contained a heap buffer overflow. A physically proximate attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2019-9500) Hugues Anguelkov discovered that the Broadcom Wifi driver in the Linux kernel did not properly prevent remote firmware events from being processed for USB Wifi devices. A physically proximate attacker could use this to send firmware events to the device. (CVE-2019-9503)

USN-3980-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.10. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.10 for Ubuntu 18.04 LTS. Ke Sun, Henrique Kawakami, Kekai Hu, Rodrigo Branco, Giorgi Maisuradze, Dan Horea Lutas, Andrei Lutas, Volodymyr Pikhur, Stephan van Schaik, Alyssa Milburn, Sebastian Österlund, Pietro Frigo, Kaveh Razavi, Herbert Bos, Cristiano Giuffrida, Moritz Lipp, Michael Schwarz, and Daniel Gruss discovered that memory previously stored in microarchitectural fill buffers of an Intel CPU core may be exposed to a malicious process that is executing on the same CPU core. A local attacker could use this to expose sensitive information. (CVE-2018-12130) Brandon Falk, Ke Sun, Henrique Kawakami, Kekai Hu, Rodrigo Branco, Stephan van Schaik, Alyssa Milburn, Sebastian Österlund, Pietro Frigo, Kaveh Razavi, Herbert Bos, and Cristiano Giuffrida discovered that memory previously stored in microarchitectural load ports of an Intel CPU core may be exposed to a malicious process that is executing on the same CPU core. A local attacker could use this to expose sensitive information. (CVE-2018-12127) Ke Sun, Henrique Kawakami, Kekai Hu, Rodrigo Branco, Marina Minkin, Daniel Moghimi, Moritz Lipp, Michael Schwarz, Jo Van Bulck, Daniel Genkin, Daniel Gruss, Berk Sunar, Frank Piessens, and Yuval Yarom discovered that memory previously stored in microarchitectural store buffers of an Intel CPU core may be exposed to a malicious process that is executing on the same CPU core. A local attacker could use this to expose sensitive information. (CVE-2018-12126) Vasily Averin and Evgenii Shatokhin discovered that a use-after-free vulnerability existed in the NFS41+ subsystem when multiple network namespaces are in use. A local attacker in a container could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-16884) Ke Sun, Henrique Kawakami, Kekai Hu, Rodrigo Branco, Volodrmyr Pikhur, Moritz Lipp, Michael Schwarz, Daniel Gruss, Stephan van Schaik, Alyssa Milburn, Sebastian Österlund, Pietro Frigo, Kaveh Razavi, Herbert Bos, and Cristiano Giuffrida discovered that uncacheable memory previously stored in microarchitectural buffers of an Intel CPU core may be exposed to a malicious process that is executing on the same CPU core. A local attacker could use this to expose sensitive information. (CVE-2019-11091) Matteo Croce, Natale Vinto, and Andrea Spagnolo discovered that the cgroups subsystem of the Linux kernel did not properly account for SCTP socket buffers. A local attacker could use this to cause a denial of service (system crash). (CVE-2019-3874) Alex Williamson discovered that the vfio subsystem of the Linux kernel did not properly limit DMA mappings. A local attacker could use this to cause a denial of service (memory exhaustion). (CVE-2019-3882) Marc Orr discovered that the KVM hypervisor implementation in the Linux kernel did not properly restrict APIC MSR register values when nested virtualization is used. An attacker in a guest vm could use this to cause a denial of service (host OS crash). (CVE-2019-3887) Hugues Anguelkov discovered that the Broadcom Wifi driver in the Linux kernel contained a heap buffer overflow. A physically proximate attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2019-9500) Hugues Anguelkov discovered that the Broadcom Wifi driver in the Linux kernel did not properly prevent remote firmware events from being processed for USB Wifi devices. A physically proximate attacker could use this to send firmware events to the device. (CVE-2019-9503)

USN-3931-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu 16.04 LTS and for the Linux Azure kernel for Ubuntu 14.04 LTS. M. Vefa Bicakci and Andy Lutomirski discovered that the kernel did not properly set up all arguments to an error handler callback used when running as a paravirtualized guest. An unprivileged attacker in a paravirtualized guest VM could use this to cause a denial of service (guest VM crash). (CVE-2018-14678) It was discovered that the KVM implementation in the Linux kernel on ARM 64bit processors did not properly handle some ioctls. An attacker with the privilege to create KVM-based virtual machines could use this to cause a denial of service (host system crash) or execute arbitrary code in the host. (CVE-2018-18021) Mathias Payer and Hui Peng discovered a use-after-free vulnerability in the Advanced Linux Sound Architecture (ALSA) subsystem. A physically proximate attacker could use this to cause a denial of service (system crash). (CVE-2018-19824) Shlomi Oberman, Yuli Shapiro, and Ran Menscher discovered an information leak in the Bluetooth implementation of the Linux kernel. An attacker within Bluetooth range could use this to expose sensitive information (kernel memory). (CVE-2019-3459, CVE-2019-3460) Jann Horn discovered that the KVM implementation in the Linux kernel contained a use-after-free vulnerability. An attacker in a guest VM with access to /dev/kvm could use this to cause a denial of service (guest VM crash). (CVE-2019-6974) Jim Mattson and Felix Wilhelm discovered a use-after-free vulnerability in the KVM subsystem of the Linux kernel, when using nested virtual machines. A local attacker in a guest VM could use this to cause a denial of service (system crash) or possibly execute arbitrary code in the host system. (CVE-2019-7221) Felix Wilhelm discovered that an information leak vulnerability existed in the KVM subsystem of the Linux kernel, when nested virtualization is used. A local attacker could use this to expose sensitive information (host system memory to a guest VM). (CVE-2019-7222) Jann Horn discovered that the eBPF implementation in the Linux kernel was insufficiently hardened against Spectre V1 attacks. A local attacker could use this to expose sensitive information. (CVE-2019-7308) It was discovered that a use-after-free vulnerability existed in the user- space API for crypto (afalg) implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2019-8912) It was discovered that the Linux kernel did not properly deallocate memory when handling certain errors while reading files. A local attacker could use this to cause a denial of service (excessive memory consumption). (CVE-2019-8980) Jann Horn discovered that the mmap implementation in the Linux kernel did not properly check for the mmap minimum address in some situations. A local attacker could use this to assist exploiting a kernel NULL pointer dereference vulnerability. (CVE-2019-9213)

USN-3930-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.10. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.10 for Ubuntu 18.04 LTS. Mathias Payer and Hui Peng discovered a use-after-free vulnerability in the Advanced Linux Sound Architecture (ALSA) subsystem. A physically proximate attacker could use this to cause a denial of service (system crash). (CVE-2018-19824) Shlomi Oberman, Yuli Shapiro, and Ran Menscher discovered an information leak in the Bluetooth implementation of the Linux kernel. An attacker within Bluetooth range could use this to expose sensitive information (kernel memory). (CVE-2019-3459, CVE-2019-3460) Jann Horn discovered that the KVM implementation in the Linux kernel contained a use-after-free vulnerability. An attacker in a guest VM with access to /dev/kvm could use this to cause a denial of service (guest VM crash). (CVE-2019-6974) Jim Mattson and Felix Wilhelm discovered a use-after-free vulnerability in the KVM subsystem of the Linux kernel, when using nested virtual machines. A local attacker in a guest VM could use this to cause a denial of service (system crash) or possibly execute arbitrary code in the host system. (CVE-2019-7221) Felix Wilhelm discovered that an information leak vulnerability existed in the KVM subsystem of the Linux kernel, when nested virtualization is used. A local attacker could use this to expose sensitive information (host system memory to a guest VM). (CVE-2019-7222) Jann Horn discovered that the eBPF implementation in the Linux kernel was insufficiently hardened against Spectre V1 attacks. A local attacker could use this to expose sensitive information. (CVE-2019-7308) It was discovered that a use-after-free vulnerability existed in the user- space API for crypto (afalg) implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2019-8912) Jakub Jirasek discovered a use-after-free vulnerability in the SCTP implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2019-8956) It was discovered that the Linux kernel did not properly deallocate memory when handling certain errors while reading files. A local attacker could use this to cause a denial of service (excessive memory consumption). (CVE-2019-8980) It was discovered that a use-after-free vulnerability existed in the IPMI implementation in the Linux kernel. A local attacker with access to the IPMI character device files could use this to cause a denial of service (system crash). (CVE-2019-9003) Jann Horn discovered that the SNMP NAT implementation in the Linux kernel performed insufficient ASN.1 length checks. An attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2019-9162) Jann Horn discovered that the mmap implementation in the Linux kernel did not properly check for the mmap minimum address in some situations. A local attacker could use this to assist exploiting a kernel NULL pointer dereference vulnerability. (CVE-2019-9213)

USN-3901-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu 16.04 LTS. Jann Horn discovered that the userfaultd implementation in the Linux kernel did not properly restrict access to certain ioctls. A local attacker could use this possibly to modify files. (CVE-2018-18397) It was discovered that the crypto subsystem of the Linux kernel leaked uninitialized memory to user space in some situations. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2018-19854) Jann Horn discovered a race condition in the fork() system call in the Linux kernel. A local attacker could use this to gain access to services that cache authorizations. (CVE-2019-6133)

USN-3871-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu 16.04 LTS. Wen Xu discovered that a use-after-free vulnerability existed in the ext4 filesystem implementation in the Linux kernel. An attacker could use this to construct a malicious ext4 image that, when mounted, could cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-10876, CVE-2018-10879) Wen Xu discovered that a buffer overflow existed in the ext4 filesystem implementation in the Linux kernel. An attacker could use this to construct a malicious ext4 image that, when mounted, could cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-10877) Wen Xu discovered that an out-of-bounds write vulnerability existed in the ext4 filesystem implementation in the Linux kernel. An attacker could use this to construct a malicious ext4 image that, when mounted, could cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-10878, CVE-2018-10882) Wen Xu discovered that the ext4 filesystem implementation in the Linux kernel did not properly ensure that xattr information remained in inode bodies. An attacker could use this to construct a malicious ext4 image that, when mounted, could cause a denial of service (system crash). (CVE-2018-10880) Wen Xu discovered that the ext4 file system implementation in the Linux kernel could possibly perform an out of bounds write when updating the journal for an inline file. An attacker could use this to construct a malicious ext4 image that, when mounted, could cause a denial of service (system crash). (CVE-2018-10883) It was discovered that a race condition existed in the vsock address family implementation of the Linux kernel that could lead to a use-after-free condition. A local attacker in a guest virtual machine could use this to expose sensitive information (host machine kernel memory). (CVE-2018-14625) Cfir Cohen discovered that a use-after-free vulnerability existed in the KVM implementation of the Linux kernel, when handling interrupts in environments where nested virtualization is in use (nested KVM virtualization is not enabled by default in Ubuntu kernels). A local attacker in a guest VM could possibly use this to gain administrative privileges in a host machine. (CVE-2018-16882) Jann Horn discovered that the procfs file system implementation in the Linux kernel did not properly restrict the ability to inspect the kernel stack of an arbitrary task. A local attacker could use this to expose sensitive information. (CVE-2018-17972) Jann Horn discovered that the mremap() system call in the Linux kernel did not properly flush the TLB when completing, potentially leaving access to a physical page after it has been released to the page allocator. A local attacker could use this to cause a denial of service (system crash), expose sensitive information, or possibly execute arbitrary code. (CVE-2018-18281) Wei Wu discovered that the KVM implementation in the Linux kernel did not properly ensure that ioapics were initialized. A local attacker could use this to cause a denial of service (system crash). (CVE-2018-19407) It was discovered that the debug interface for the Linux kernel's HID subsystem did not properly perform bounds checking in some situations. An attacker with access to debugfs could use this to cause a denial of service or possibly gain additional privileges. (CVE-2018-9516)

USN-3847-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu 16.04 LTS. It was discovered that a race condition existed in the raw MIDI driver for the Linux kernel, leading to a double free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-10902) It was discovered that an integer overrun vulnerability existed in the POSIX timers implementation in the Linux kernel. A local attacker could use this to cause a denial of service. (CVE-2018-12896) Noam Rathaus discovered that a use-after-free vulnerability existed in the Infiniband implementation in the Linux kernel. An attacker could use this to cause a denial of service (system crash). (CVE-2018-14734) It was discovered that the YUREX USB device driver for the Linux kernel did not properly restrict user space reads or writes. A physically proximate attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-16276) It was discovered that the BPF verifier in the Linux kernel did not correctly compute numeric bounds in some situations. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-18445) Kanda Motohiro discovered that writing extended attributes to an XFS file system in the Linux kernel in certain situations could cause an error condition to occur. A local attacker could use this to cause a denial of service. (CVE-2018-18690) It was discovered that an integer overflow vulnerability existed in the CDROM driver of the Linux kernel. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2018-18710)

USN-3836-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu 16.04 LTS. Jann Horn discovered that the Linux kernel mishandles mapping UID or GID ranges inside nested user namespaces in some situations. A local attacker could use this to bypass access controls on resources outside the namespace. (CVE-2018-18955) Philipp Wendler discovered that the overlayfs implementation in the Linux kernel did not properly verify the directory contents permissions from within a unprivileged user namespace. A local attacker could use this to expose sensitive information (protected file names). (CVE-2018-6559)

USN-3777-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu 16.04 LTS. Jann Horn discovered that the vmacache subsystem did not properly handle sequence number overflows, leading to a use-after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or execute arbitrary code. (CVE-2018-17182) It was discovered that the paravirtualization implementation in the Linux kernel did not properly handle some indirect calls, reducing the effectiveness of Spectre v2 mitigations for paravirtual guests. A local attacker could use this to expose sensitive information. (CVE-2018-15594) It was discovered that microprocessors utilizing speculative execution and prediction of return addresses via Return Stack Buffer (RSB) may allow unauthorized memory reads via sidechannel attacks. An attacker could use this to expose sensitive information. (CVE-2018-15572) Andy Lutomirski and Mika Penttilä discovered that the KVM implementation in the Linux kernel did not properly check privilege levels when emulating some instructions. An unprivileged attacker in a guest VM could use this to escalate privileges within the guest. (CVE-2018-10853) It was discovered that a stack-based buffer overflow existed in the iSCSI target implementation of the Linux kernel. A remote attacker could use this to cause a denial of service (system crash). (CVE-2018-14633) It was discovered that a memory leak existed in the IRDA subsystem of the Linux kernel. A local attacker could use this to cause a denial of service (kernel memory exhaustion). (CVE-2018-6554) It was discovered that a use-after-free vulnerability existed in the IRDA implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-6555) USN 3653-2 added a mitigation for Speculative Store Bypass a.k.a. Spectre Variant 4 (CVE-2018-3639). This update provides the corresponding mitigation for ARM64 processors. Please note that for this mitigation to be effective, an updated firmware for the processor may be required. '

USN-3762-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu 16.04 LTS. It was discovered that the VirtIO subsystem in the Linux kernel did not properly initialize memory in some situations. A local attacker could use this to possibly expose sensitive information (kernel memory). (CVE-2018-1118) Seunghun Han discovered an information leak in the ACPI handling code in the Linux kernel when handling early termination of ACPI table loading. A local attacker could use this to expose sensitive informal (kernel address locations). (CVE-2017-13695)

USN-3752-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu 16.04 LTS. It was discovered that, when attempting to handle an out-of-memory situation, a null pointer dereference could be triggered in the Linux kernel in some circumstances. A local attacker could use this to cause a denial of service (system crash). (CVE-2018-1000200) Wen Xu discovered that the XFS filesystem implementation in the Linux kernel did not properly validate meta-data information. An attacker could use this to construct a malicious xfs image that, when mounted, could cause a denial of service (system crash). (CVE-2018-10323) Wen Xu discovered that the XFS filesystem implementation in the Linux kernel did not properly validate xattr information. An attacker could use this to construct a malicious xfs image that, when mounted, could cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-10840) Wen Xu discovered that the ext4 filesystem implementation in the Linux kernel did not properly keep meta-data information consistent in some situations. An attacker could use this to construct a malicious ext4 image that, when mounted, could cause a denial of service (system crash). (CVE-2018-10881) Wen Xu discovered that the ext4 filesystem implementation in the Linux kernel did not properly handle corrupted meta data in some situations. An attacker could use this to specially craft an ext4 filesystem that caused a denial of service (system crash) when mounted. (CVE-2018-1093) Jann Horn discovered that the Linux kernel's implementation of random seed data reported that it was in a ready state before it had gathered sufficient entropy. An attacker could use this to expose sensitive information. (CVE-2018-1108) It was discovered that the procfs filesystem did not properly handle processes mapping some memory elements onto files. A local attacker could use this to block utilities that examine the procfs filesystem to report operating system state, such as ps(1). (CVE-2018-1120) Jann Horn discovered that the ext4 filesystem implementation in the Linux kernel did not properly keep xattr information consistent in some situations. An attacker could use this to construct a malicious ext4 image that, when mounted, could cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-11412) Piotr Gabriel Kosinski and Daniel Shapira discovered a stack-based buffer overflow in the CDROM driver implementation of the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-11506) Shankara Pailoor discovered that a race condition existed in the socket handling code in the Linux kernel. A local attacker could use this to cause a denial of service (system crash). (CVE-2018-12232) Shankara Pailoor discovered that the JFS filesystem implementation in the Linux kernel contained a buffer overflow when handling extended attributes. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-12233) Felix Wilhelm discovered that the KVM implementation in the Linux kernel did not properly perform permission checks in some situations when nested virtualization is used. An attacker in a guest VM could possibly use this to escape into an outer VM or the host OS. (CVE-2018-12904) Wen Xu discovered that the XFS filesystem implementation in the Linux kernel did not properly handle an error condition with a corrupted xfs image. An attacker could use this to construct a malicious xfs image that, when mounted, could cause a denial of service (system crash). (CVE-2018-13094) It was discovered that the Linux kernel did not properly handle setgid file creation when performed by a non-member of the group. A local attacker could use this to gain elevated privileges. (CVE-2018-13405) Silvio Cesare discovered that the generic VESA frame buffer driver in the Linux kernel contained an integer overflow. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-13406) Jakub Jirasek discovered that multiple use-after-free errors existed in the USB/IP implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-5814) It was discovered that a race condition existed in the ARM Advanced Microcontroller Bus Architecture (AMBA) driver in the Linux kernel that could result in a double free. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-9415) It was discovered that an information leak existed in the generic SCSI driver in the Linux kernel. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2018-1000204)

USN-3740-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu 16.04 LTS. It was discovered that memory present in the L1 data cache of an Intel CPU core may be exposed to a malicious process that is executing on the CPU core. This vulnerability is also known as L1 Terminal Fault (L1TF). A local attacker in a guest virtual machine could use this to expose sensitive information (memory from other guests or the host OS). (CVE-2018-3646) It was discovered that memory present in the L1 data cache of an Intel CPU core may be exposed to a malicious process that is executing on the CPU core. This vulnerability is also known as L1 Terminal Fault (L1TF). A local attacker could use this to expose sensitive information (memory from the kernel or other processes). (CVE-2018-3620) Juha-Matti Tilli discovered that the IP implementation in the Linux kernel performed algorithmically expensive operations in some situations when handling incoming packet fragments. A remote attacker could use this to cause a denial of service. (CVE-2018-5391)

USN-3677-1 fixed vulnerabilities in the Linux kernel for Ubuntu 17.10. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 17.10 for Ubuntu 16.04 LTS. It was discovered that the netfilter subsystem of the Linux kernel did not properly validate ebtables offsets. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-1068) Wen Xu discovered that the ext4 filesystem implementation in the Linux kernel did not properly handle corrupted meta data in some situations. An attacker could use this to specially craft an ext4 file system that caused a denial of service (system crash) when mounted. (CVE-2018-1092) It was discovered that a NULL pointer dereference existed in the RDS (Reliable Datagram Sockets) protocol implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash). (CVE-2018-7492) It was discovered that the 802.11 software simulator implementation in the Linux kernel contained a memory leak when handling certain error conditions. A local attacker could possibly use this to cause a denial of service (memory exhaustion). (CVE-2018-8087) Eyal Itkin discovered that the USB displaylink video adapter driver in the Linux kernel did not properly validate mmap offsets sent from userspace. A local attacker could use this to expose sensitive information (kernel memory) or possibly execute arbitrary code. (CVE-2018-8781)

USN-3617-1 fixed vulnerabilities in the Linux kernel for Ubuntu 17.10. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 17.10 for Ubuntu 16.04 LTS. It was discovered that a race condition leading to a use-after-free vulnerability existed in the ALSA PCM subsystem of the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2017-0861) It was discovered that the KVM implementation in the Linux kernel allowed passthrough of the diagnostic I/O port 0x80. An attacker in a guest VM could use this to cause a denial of service (system crash) in the host OS. (CVE-2017-1000407) It was discovered that a use-after-free vulnerability existed in the network namespaces implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2017-15129) Andrey Konovalov discovered that the usbtest device driver in the Linux kernel did not properly validate endpoint metadata. A physically proximate attacker could use this to cause a denial of service (system crash). (CVE-2017-16532) Andrey Konovalov discovered that the SoundGraph iMON USB driver in the Linux kernel did not properly validate device metadata. A physically proximate attacker could use this to cause a denial of service (system crash). (CVE-2017-16537) Andrey Konovalov discovered that the IMS Passenger Control Unit USB driver in the Linux kernel did not properly validate device descriptors. A physically proximate attacker could use this to cause a denial of service (system crash). (CVE-2017-16645) Andrey Konovalov discovered that the DiBcom DiB0700 USB DVB driver in the Linux kernel did not properly handle detach events. A physically proximate attacker could use this to cause a denial of service (system crash). (CVE-2017-16646) Andrey Konovalov discovered that the ASIX Ethernet USB driver in the Linux kernel did not properly handle suspend and resume events. A physically proximate attacker could use this to cause a denial of service (system crash). (CVE-2017-16647) Andrey Konovalov discovered that the CDC USB Ethernet driver did not properly validate device descriptors. A physically proximate attacker could use this to cause a denial of service (system crash). (CVE-2017-16649) Andrey Konovalov discovered that the QMI WWAN USB driver did not properly validate device descriptors. A physically proximate attacker could use this to cause a denial of service (system crash). (CVE-2017-16650) It was discovered that the HugeTLB component of the Linux kernel did not properly handle holes in hugetlb ranges. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2017-16994) It was discovered that the netfilter component of the Linux did not properly restrict access to the connection tracking helpers list. A local attacker could use this to bypass intended access restrictions. (CVE-2017-17448) It was discovered that the netfilter passive OS fingerprinting (xtosf) module did not properly perform access control checks. A local attacker could improperly modify the system-wide OS fingerprint list. (CVE-2017-17450) Dmitry Vyukov discovered that the KVM implementation in the Linux kernel contained an out-of-bounds read when handling memory-mapped I/O. A local attacker could use this to expose sensitive information. (CVE-2017-17741) It was discovered that the Salsa20 encryption algorithm implementations in the Linux kernel did not properly handle zero-length inputs. A local attacker could use this to cause a denial of service (system crash). (CVE-2017-17805) It was discovered that the HMAC implementation did not validate the state of the underlying cryptographic hash algorithm. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2017-17806) It was discovered that the keyring implementation in the Linux kernel did not properly check permissions when a key request was performed on a task's default keyring. A local attacker could use this to add keys to unauthorized keyrings. (CVE-2017-17807) It was discovered that a race condition existed in the OCFS2 file system implementation in the Linux kernel. A local attacker could use this to cause a denial of service (kernel deadlock). (CVE-2017-18204) It was discovered that the Broadcom NetXtremeII ethernet driver in the Linux kernel did not properly validate Generic Segment Offload (GSO) packet sizes. An attacker could use this to cause a denial of service (interface unavailability). (CVE-2018-1000026) It was discovered that the Reliable Datagram Socket (RDS) implementation in the Linux kernel contained an out-of-bounds write during RDMA page allocation. An attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-5332) Mohamed Ghannam discovered a null pointer dereference in the RDS (Reliable Datagram Sockets) protocol implementation of the Linux kernel. A local attacker could use this to cause a denial of service (system crash). (CVE-2018-5333) 范龙飞 discovered that a race condition existed in loop block device implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-5344)

USN-3597-1 fixed vulnerabilities in the Linux kernel for Ubuntu 17.10. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 17.10 for Ubuntu 16.04 LTS. USNS 3541-2 and 3523-2 provided mitigations for Spectre and Meltdown (CVE-2017-5715, CVE-2017-5753, CVE-2017-5754) for the i386, amd64, and ppc64el architectures for Ubuntu 16.04 LTS. This update provides the corresponding mitigations for the arm64 architecture. Original advisory details: Jann Horn discovered that microprocessors utilizing speculative execution and indirect branch prediction may allow unauthorized memory reads via sidechannel attacks. This flaw is known as Meltdown. A local attacker could use this to expose sensitive information, including kernel memory. (CVE-2017-5754) Jann Horn discovered that microprocessors utilizing speculative execution and branch prediction may allow unauthorized memory reads via sidechannel attacks. This flaw is known as Spectre. A local attacker could use this to expose sensitive information, including kernel memory. (CVE-2017-5715, CVE-2017-5753)

USN-3581-1 fixed vulnerabilities in the Linux kernel for Ubuntu 17.10. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 17.10 for Ubuntu 16.04 LTS. Mohamed Ghannam discovered that the IPv4 raw socket implementation in the Linux kernel contained a race condition leading to uninitialized pointer usage. A local attacker could use this to cause a denial of service or possibly execute arbitrary code. (CVE-2017-17712) ChunYu Wang discovered that a use-after-free vulnerability existed in the SCTP protocol implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code, (CVE-2017-15115) Mohamed Ghannam discovered a use-after-free vulnerability in the DCCP protocol implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2017-8824) USN-3541-2 mitigated CVE-2017-5715 (Spectre Variant 2) for the amd64 architecture in Ubuntu 16.04 LTS. This update provides the compiler-based retpoline kernel mitigation for the amd64 and i386 architectures. Original advisory details: Jann Horn discovered that microprocessors utilizing speculative execution and branch prediction may allow unauthorized memory reads via sidechannel attacks. This flaw is known as Spectre. A local attacker could use this to expose sensitive information, including kernel memory. (CVE-2017-5715)

USN-3523-1 fixed vulnerabilities in the Linux kernel for Ubuntu 17.10. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 17.10 for Ubuntu 16.04 LTS. Jann Horn discovered that microprocessors utilizing speculative execution and indirect branch prediction may allow unauthorized memory reads via sidechannel attacks. This flaw is known as Meltdown. A local attacker could use this to expose sensitive information, including kernel memory. (CVE-2017-5754) Jann Horn discovered that the Berkeley Packet Filter (BPF) implementation in the Linux kernel did not properly check the relationship between pointer values and the BPF stack. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2017-17863) Jann Horn discovered that the Berkeley Packet Filter (BPF) implementation in the Linux kernel improperly performed sign extension in some situations. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2017-16995) Alexei Starovoitov discovered that the Berkeley Packet Filter (BPF) implementation in the Linux kernel contained a branch-pruning logic issue around unreachable code. A local attacker could use this to cause a denial of service. (CVE-2017-17862) Jann Horn discovered that the Berkeley Packet Filter (BPF) implementation in the Linux kernel mishandled pointer data values in some situations. A local attacker could use this to to expose sensitive information (kernel memory). (CVE-2017-17864)