A flaw in the Linux Kernel found. If unprivileged users can mount FUSE filesystems, then can trigger use after free (UAF) that reads of write() buffers, allowing theft of (partial) /etc/shadow hashes or any other data from filesystem.

FUSE allows the userspace filesystem to specify on FUSEOPEN whether the file should use the normal kernel pagecache for handling read()/write() or just send FUSEREAD/FUSEWRITE requests directly to the userspace filesystem (using the flag FOPENDIRECTIO in fuseopenout::openflags).

In FOPENDIRECTIO mode, fusefilewriteiter() calls fusedirectwriteiter(), which normally calls fusedirectio(), which then imports the write buffer with fusegetuserpages(), which uses iovitergetpages() to grab references to userspace pages instead of actually copying memory.

On the filesystem device side, these pages can then either be read to userspace (via fusedevread()), or splice()d over into a pipe using fusedevspliceread() as pipe buffers with &nostealpipebufops.

This is wrong because after fusedevdoread() unlocks the FUSE request, the userspace filesystem can mark the request as completed, causing write() to return. At that point, the write buffer may be reused for other purposes, and the userspace filesystem should no longer have access to it.

A random memory access flaw was found in the Linux kernel's GPU i915 kernel driver functionality in the way a user may run malicious code on the GPU. This flaw allows a local user to crash the system or escalate their privileges on the system.

A flaw was found in the Linux kernel in versions before 5.12. The value of internal.ndata, in the KVM API, is mapped to an array index, which can be updated by a user process at anytime which could lead to an out-of-bounds write. The highest threat from this vulnerability is to data integrity and system availability.

A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copypagetoiterpipe and pushpipe functions in the Linux kernel and could thus contain stale values. An unprivileged local user could use this flaw to write to pages in the page cache backed by read only files and as such escalate their privileges on the system.

A flaw was discovered in the Bluetooth protocol. An attacker within physical proximity to the Bluetooth connection could downgrade the encryption protocol to be trivially brute forced.

An information leakage issue was found in the way Linux kernel's KVM hypervisor handled page fault exception while emulating instructions like VMXON, VMCLEAR, VMPTRLD, VMWRITE with memory address as an operand. It occurs if the operand is an mmio address, as the returned exception object holds uninitialised stack memory contents.

A guest user/process could use this flaw to leak host's stack memory contents to a guest.

It affects only Intel processors and only when nested virtualization is enabled.

Upstream patch: --------------- -> https://git.kernel.org/linus/353c0956a618a07ba4bbe7ad00ff29fe70e8412a

Reference: ---------- -> https://www.openwall.com/lists/oss-security/2019/02/18/2

A flaw was found in the way KVM hypervisor handled x2APIC Machine Specific Rregister(MSR) access with nested(=1) virtualization enabled. In that, L1 guest could access L0's APIC register values via L2 guest, when 'virtualize x2APIC mode' is enabled.

A guest could use this flaw to potentially crash the host kernel resulting in DoS issue.

Upstream patches: ----------------- -> https://git.kernel.org/pub/scm/virt/kvm/kvm.git/commit/?id=acff78477b9b4f26ecdf65733a4ed77fe837e9dc -> https://git.kernel.org/pub/scm/virt/kvm/kvm.git/commit/?id=c73f4c998e1fd4249b9edfa39e23f4fda2b9b041

Reference: ---------- -> https://www.openwall.com/lists/oss-security/2019/04/08/1

A flaw was found in the Linux kernel's implementation of Logical Link Control and Adaptation Protocol (L2CAP), part of the Bluetooth stack. An attacker, within the range of standard Bluetooth transmissions, can create and send a specially crafted packet. The response to this specially crafted packet can contain part of the kernel stack which can be used in a further attack.

A flaw was found in the Linux kernel's implementation of logical link control and adaptation protocol (L2CAP), part of the Bluetooth stack in the l2capparseconfrsp and l2capparseconfreq functions. An attacker with physical access within the range of standard Bluetooth transmission can create a specially crafted packet. The response to this specially crafted packet can contain part of the kernel stack which can be used in a further attack.

A flaw in the kernels implementation of ptrace which could inadvertantly grant elevated permissions to an attacker who could abuse the relationship between tracer and the process being traced.

The mechanism used to link the process requesting the ptrace and the process being ptraced could allow a local user to obtain root level priviledges by creating an opportunity to abuse the frequently used pattern of dropping privileges and then execve a child with reduced privileges/permissions.

References: https://bugs.chromium.org/p/project-zero/issues/detail?id=1903 https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.1.17 https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6994eefb0053799d2e07cd140df6c2ea106c41ee https://github.com/torvalds/linux/commit/6994eefb0053799d2e07cd140df6c2ea106c41ee

A flaw was found in the kernels implementation of the bluetooth HIDP (Human Interface Device Protocol). A local attacker with access permissions to the bluetooth device can issue an IOCTL which will trigger the dohidpsockioctl function in net/bluetooth/hidp/sock.c.c. This function can potentially leak potentially sensitive information from kernel stack memory via a HIDPCONNADD command, because a name field may not correctly NULL terminated.

Reference: https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.0.15

Upstream commit: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=a1616a5ac99ede5d605047a9012481ce7ff18b16 https://github.com/torvalds/linux/commit/a1616a5ac99ede5d605047a9012481ce7ff18b16

A flaw was found in the Linux kernel's implementation of ext4 extent management. The kernel doesn't correctly initialize memory regions in the extent tree block which may be exported to a local user to obtain sensitive information by reading empty/uninitialized data from the filesystem.

A flaw was found in the Linux kernel. A heap based buffer overflow in mwifiexuapparsetailies function in drivers/net/wireless/marvell/mwifiex/ie.c might lead to memory corruption and possibly other consequences.

In the Linux kernel before 4.20.2, kernel/sched/fair.c mishandles leaf cfsrq's, which allows attackers to cause a denial of service (infinite loop in updateblockedaverages) or possibly have unspecified other impact by inducing a high load.

A vulnerability was found in the fs/inode.c:inodeinitowner() function logic of the LInux kernel that allows local users to create files with an unintended group ownership and with group execution and SGID permission bits set, in a scenario where a directory is SGID and belongs to a certain group and is writable by a user who is not a member of this group. This can lead to excessive permissions granted in case when they should not.

A flaw was found in Linux kernel ext4 filesystem. A local user can cause an out-of-bound access in ext4getgroupinfo function and so a denial of service and a system crash by mounting and operating on a crafted ext4 filesystem image.

References:

https://bugzilla.kernel.org/showbug.cgi?id=200015

http://patchwork.ozlabs.org/patch/929792/

An upstream patch:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6e8ab72a812396996035a37e5ca4b3b99b5d214b

Last updated 4 July 2026

A flaw was found in the Linux kernel's NVMe driver. This issue may allow an unauthenticated malicious actor to send a set of crafted TCP packages when using NVMe over TCP, leading the NVMe driver to a NULL pointer dereference in the NVMe driver, causing kernel panic and a denial of service.

A double free vulnerability was found in the vmwgfx driver in the Linux kernel. Quoting ZDI security advisory [1]:

"This vulnerability allows local attackers to escalate privileges on affected installations of Linux Kernel. An attacker must first obtain the ability to execute high-privileged code on the target system in order to exploit this vulnerability.

The specific flaw exists within the handling of vmwbufferobject objects. The issue results from the lack of validating the existence of an object prior to performing further free operations on the object. An attacker can leverage this vulnerability to escalate privileges and execute code in the context of the kernel."

[1] https://www.zerodayinitiative.com/advisories/ZDI-CAN-20292/

========== 1. Null-ptr-deref in xfrmupdateaeparams() ==========

[require privilege]: CAPNETADMIN

[effects]: local DoS

[crash stack]: [ 47.933119] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 47.933119] #PF: supervisor write access in kernel mode [ 47.933119] #PF: errorcode(0x0002) - not-present page [ 47.933119] PGD 8253067 P4D 8253067 PUD 8e0e067 PMD 0 [ 47.933119] Oops: 0002 [#1] PREEMPT SMP KASAN NOPTI [ 47.933119] CPU: 0 PID: 98 Comm: poc.npd Not tainted 6.4.0-rc7-00072-gdad9774deaf1 #8 [ 47.933119] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.o4 [ 47.933119] RIP: 0010:memcpyorig+0xad/0x140 [ 47.933119] Code: e8 4c 89 5f e0 48 8d 7f e0 73 d2 83 c2 20 48 29 d6 48 29 d7 83 fa 10 72 34 4c 8b 06 4c 8b 4e 08 c [ 47.933119] RSP: 0018:ffff888008f57658 EFLAGS: 00000202 [ 47.933119] RAX: 0000000000000000 RBX: ffff888008bd0000 RCX: ffffffff8238e571 [ 47.933119] RDX: 0000000000000018 RSI: ffff888007f64844 RDI: 0000000000000000 [ 47.933119] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 47.933119] R10: 0000000000000000 R11: 0000000000000000 R12: ffff888008f57818 [ 47.933119] R13: ffff888007f64aa4 R14: 0000000000000000 R15: 0000000000000000 [ 47.933119] FS: 00000000014013c0(0000) GS:ffff88806d600000(0000) knlGS:0000000000000000 [ 47.933119] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 47.933119] CR2: 0000000000000000 CR3: 00000000054d8000 CR4: 00000000000006f0 [ 47.933119] Call Trace: [ 47.933119] <TASK> [ 47.933119] ? die+0x1f/0x70 [ 47.933119] ? pagefaultoops+0x1e8/0x500 [ 47.933119] ? pfxisprefetch.constprop.0+0x10/0x10 [ 47.933119] ? pfxpagefaultoops+0x10/0x10 [ 47.933119] ? rawspinunlockirqrestore+0x11/0x40 [ 47.933119] ? fixupexception+0x36/0x460 [ 47.933119] ? rawspinunlockirqrestore+0x11/0x40 [ 47.933119] ? excpagefault+0x5e/0xc0 [ 47.933119] ? asmexcpagefault+0x26/0x30 [ 47.933119] ? xfrmupdateaeparams+0xd1/0x260 [ 47.933119] ? memcpyorig+0xad/0x140 [ 47.933119] ? pfxrawspinlockbh+0x10/0x10 [ 47.933119] xfrmupdateaeparams+0xe7/0x260 [ 47.933119] xfrmnewae+0x298/0x4e0 [ 47.933119] ? pfxxfrmnewae+0x10/0x10 [ 47.933119] xfrmuserrcvmsg+0x25a/0x410 [ 47.933119] ? pfxxfrmuserrcvmsg+0x10/0x10 [ 47.933119] ? allocskb+0xcf/0x210 [ 47.933119] ? stacktracesave+0x90/0xd0 [ 47.933119] ? filterirqstacks+0x1c/0x70 [ 47.933119] ? stackdepotsave+0x39/0x4e0 [ 47.933119] ? kasanslabfree+0x10a/0x190 [ 47.933119] ? kmemcachefree+0x9c/0x340 [ 47.933119] ? netlinkrecvmsg+0x23c/0x660 [ 47.933119] ? sockrecvmsg+0xeb/0xf0 [ 47.933119] ? sysrecvfrom+0x13c/0x1f0 [ 47.933119] ? x64sysrecvfrom+0x71/0x90 [ 47.933119] ? dosyscall64+0x3f/0x90 [ 47.933119] ? entrySYSCALL64afterhwframe+0x72/0xdc [ 47.933119] ? copyout+0x3e/0x50 [ 47.933119] netlinkrcvskb+0xd6/0x210 [ 47.933119] ? pfxxfrmuserrcvmsg+0x10/0x10 [ 47.933119] ? pfxnetlinkrcvskb+0x10/0x10 [ 47.933119] ? pfxsockhasperm+0x10/0x10 [ 47.933119] ? mutexlock+0x8d/0xe0 [ 47.933119] ? pfxmutexlock+0x10/0x10 [ 47.933119] xfrmnetlinkrcv+0x44/0x50 [ 47.933119] netlinkunicast+0x36f/0x4c0 [ 47.933119] ? pfxnetlinkunicast+0x10/0x10 [ 47.933119] ? netlinkrecvmsg+0x500/0x660 [ 47.933119] netlinksendmsg+0x3b7/0x700 [ 47.933119] ? pfxnetlinksendmsg+0x10/0x10 [ 47.933119] ? updateloadavg+0x591/0xab0 [ 47.933119] ? pfxnetlinksendmsg+0x10/0x10 [ 47.933119] socksendmsg+0xde/0xe0 [ 47.933119] syssendto+0x18d/0x230 [ 47.933119] ? pfxsyssendto+0x10/0x10 [ 47.933119] ? rbinsertcolor+0x1c0/0x280 [ 47.933119] ? timerqueueadd+0x128/0x150 [ 47.933119] ? ktimeget+0x49/0xb0 [ 47.933119] ? pfxnativeapicmemwrite+0x10/0x10 [ 47.933119] ? lapicnextevent+0x35/0x40 [ 47.933119] ? clockeventsprogramevent+0xdf/0x140 [ 47.933119] ? hrtimerinterrupt+0x321/0x360 [ 47.933119] x64syssendto+0x71/0x90 [ 47.933119] dosyscall64+0x3f/0x90 [ 47.933119] entrySYSCALL64afterhwframe+0x72/0xdc [ 47.933119] RIP: 0033:0x44b8aa [ 47.933119] Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb b9 0f 1f 00 f3 0f 1e fa 41 89 ca 64 8b 04 25 18 00 00 00 85 9 [ 47.933119] RSP: 002b:00007fff7ded8258 EFLAGS: 00000246 ORIGRAX: 000000000000002c [ 47.933119] RAX: ffffffffffffffda RBX: 00007fff7ded9688 RCX: 000000000044b8aa [ 47.933119] RDX: 00000000000002a8 RSI: 00007fff7ded8480 RDI: 0000000000000003 [ 47.933119] RBP: 00007fff7ded82c0 R08: 00007fff7ded829c R09: 000000000000000c [ 47.933119] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 47.933119] R13: 00007fff7ded9678 R14: 00000000004c37d0 R15: 0000000000000001 [ 47.933119] </TASK> [ 47.933119] Modules linked in: [ 47.933119] CR2: 0000000000000000 [ 47.933119] ---[ end trace 0000000000000000 ]--- [ 47.933119] RIP: 0010:memcpyorig+0xad/0x140 [ 47.933119] Code: e8 4c 89 5f e0 48 8d 7f e0 73 d2 83 c2 20 48 29 d6 48 29 d7 83 fa 10 72 34 4c 8b 06 4c 8b 4e 08 c [ 47.933119] RSP: 0018:ffff888008f57658 EFLAGS: 00000202 [ 47.933119] RAX: 0000000000000000 RBX: ffff888008bd0000 RCX: ffffffff8238e571 [ 47.933119] RDX: 0000000000000018 RSI: ffff888007f64844 RDI: 0000000000000000 [ 47.933119] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 47.933119] R10: 0000000000000000 R11: 0000000000000000 R12: ffff888008f57818 [ 47.933119] R13: ffff888007f64aa4 R14: 0000000000000000 R15: 0000000000000000 [ 47.933119] FS: 00000000014013c0(0000) GS:ffff88806d600000(0000) knlGS:0000000000000000 [ 47.933119] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 47.933119] CR2: 0000000000000000 CR3: 00000000054d8000 CR4: 00000000000006f0 [ 47.933119] Kernel panic - not syncing: Fatal exception in interrupt [ 47.933119] Kernel Offset: disabled [ 47.933119] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---

[buggy commit]: d8647b79c3b7 ("xfrm: Add user interface for esn and big anti-replay windows")

[root cause]: x->replayesn and x->preplayesn should be allocated at xfrmallocreplaystateesn(...) in xfrmstateconstruct(..), and then the xfrmupdateaeparams(...) is okay to update them. However, the current implementation allows a malicious user to directly dereference the pointer and crash the kernel like above.

[PoC code]: see attachment poc1.c. I have tested it in ubuntu 22.04 and latest Linux with QEMU.

[suggest fix]: Add NULL check in xfrmupdateaeparams() like below:

@@ -628,7 +628,7 @@ static void xfrmupdateaeparams(struct xfrmstate x, struct nlattr attrs, struct nlattr rt = attrs[XFRMAREPLAYTHRESH]; struct nlattr mt = attrs[XFRMAMTIMERTHRESH];

- if (re) { + if (re && x->replayesn && x->preplayesn) { struct xfrmreplaystateesn replayesn;

A use-after-free vulnerability was found in the siano smsusb module in the Linux kernel. The bug occurs during device initialization when the siano device is plugged in. This flaw allows a local user to crash the system, causing a denial of service condition.

A flaw was found in the Linux kernel's NVMe driver. This issue may allow an unauthenticated malicious actor to send a set of crafted TCP packages when using NVMe over TCP, leading the NVMe driver to a NULL pointer dereference in the NVMe driver and causing kernel panic and a denial of service.

A flaw was found in the Linux kernel's NVMe driver. This issue may allow an unauthenticated malicious actor to send a set of crafted TCP packages when using NVMe over TCP, leading the NVMe driver to a NULL pointer dereference in the NVMe driver, causing kernel panic and a denial of service.

A flaw was found in pfnswapentrytopage in memory management subsystem in the Linux Kernel. In this flaw, an attacker with a local user privilege may cause a denial of service problem due to a BUG statement referencing pmdt x.

A flaw in the Linux Kernel found. For the netfilter, nftablesnewrule when adding a rule with NFTARULECHAINID can lead to use-after-free.

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0ebc1064e4874d5987722a2ddbc18f94aa53b211

A race condition vulnerability was found in the vmwgfx driver in the Linux kernel. Quoting ZDI security advisory [1]:

"This vulnerability allows local attackers to disclose sensitive information on affected installations of Linux Kernel. An attacker must first obtain the ability to execute high-privileged code on the target system in order to exploit this vulnerability.

The specific flaw exists within the handling of GEM objects. The issue results from the lack of proper locking when performing operations on an object. An attacker can leverage this vulnerability to disclose information in the context of the kernel."

[1] https://www.zerodayinitiative.com/advisories/ZDI-CAN-20110/

Last updated 30 August 2024

A buffer overflow flaw was found in the way Linux kernel's vhost functionality that translates virtqueue buffers to IOVs logged the buffer descriptors during migration. A privileged guest user able to pass descriptors with invalid length to the host when migration is underway, could use this flaw to increase their privileges on the host.

A flaw was found in the Linux kernel. Measuring usage of the shared memory does not scale with large shared memory segment counts which could lead to resource exhaustion and DoS.

.A flaw was found in the CAN BCM networking protocol in the Linux kernel, where a local attacker can abuse a flaw in the CAN subsystem to corrupt memory, crash the system or escalate privileges. This race condition in net/can/bcm.c in the Linux kernel allows for local privilege escalation to root.