Concurrent removals of certain anonymous shared memory mappings by using the UMTXSHMDESTROY sub-request of UMTXOPSHM can lead to decreasing the reference count of the object representing the mapping too many times, causing it to be freed too early.

A malicious code exercizing the UMTXSHMDESTROY sub-request in parallel can panic the kernel or enable further Use-After-Free attacks, potentially including code execution or Capsicum sandbox escape.

Stack-based buffer overflow in rtsold in FreeBSD 9.1 through 10.1-RC2 allows remote attackers to cause a denial of service (crash) or possibly execute arbitrary code via crafted DNS parameters in a router advertisement message.

In FreeBSD 12.2-STABLE before r368250, 11.4-STABLE before r368253, 12.2-RELEASE before p1, 12.1-RELEASE before p11 and 11.4-RELEASE before p5 when processing a DNSSL option, rtsold(8) decodes domain name labels per an encoding specified in RFC 1035 in which the first octet of each label contains the label's length. rtsold(8) did not validate label lengths correctly and could overflow the destination buffer.

In FreeBSD 12.2-STABLE before r368250, 11.4-STABLE before r368253, 12.2-RELEASE before p1, 12.1-RELEASE before p11 and 11.4-RELEASE before p5 rtsold(8) does not verify that the RDNSS option does not extend past the end of the received packet before processing its contents. While the kernel currently ignores such malformed packets, it passes them to userspace programs. Any programs expecting the kernel to do validation may be vulnerable to an overflow.

In FreeBSD before 11.2-STABLE(r340854) and 11.2-RELEASE-p5, an integer overflow error when handling opcodes can cause memory corruption by sending a specially crafted NFSv4 request. Unprivileged remote users with access to the NFS server may be able to execute arbitrary code.

In FreeBSD before 11.2-STABLE(r341486) and 11.2-RELEASE-p6, insufficient bounds checking in one of the device models provided by bhyve can permit a guest operating system to overwrite memory in the bhyve host possibly permitting arbitrary code execution. A guest OS using a firmware image can cause the bhyve process to crash, or possibly execute arbitrary code on the host as root.

Off-by-one error in the inetnetwork function in libbind in ISC BIND 9.4.2 and earlier, as used in libc in FreeBSD 6.2 through 7.0-PRERELEASE, allows context-dependent attackers to cause a denial of service (crash) and possibly execute arbitrary code via crafted input that triggers memory corruption.

A user-provided integer option was passed to nmreqcopyin() without checking if it would overflow. This insufficient bounds checking could lead to kernel memory corruption.

On systems configured to include netmap in their devfsruleset, a privileged process running in a jail can affect the host environment.

Handlers for CFGPAGE read / write ioctls in the mpr, mps, and mpt drivers allocated a buffer of a caller-specified size, but copied to it a fixed size header. Other heap content would be overwritten if the specified size was too small.

Users with access to the mpr, mps or mpt device node may overwrite heap data, potentially resulting in privilege escalation. Note that the device node is only accessible to root and members of the operator group.

The 802.11 beacon handling routine failed to validate the length of an IEEE 802.11s Mesh ID before copying it to a heap-allocated buffer.

While a FreeBSD Wi-Fi client is in scanning mode (i.e., not associated with a SSID) a malicious beacon frame may overwrite kernel memory, leading to remote code execution.

NFS in a BSD derived codebase, as used in OpenBSD through 7.4 and FreeBSD through 14.0-RELEASE, allows remote attackers to execute arbitrary code via a bug that is unrelated to memory corruption.

In FreeBSD 12.0-STABLE before r350648, 12.0-RELEASE before 12.0-RELEASE-p9, 11.3-STABLE before r350650, 11.3-RELEASE before 11.3-RELEASE-p2, and 11.2-RELEASE before 11.2-RELEASE-p13, the ICMPv6 input path incorrectly handles cases where an MLDv2 listener query packet is internally fragmented across multiple mbufs. A remote attacker may be able to cause an out-of-bounds read or write that may cause the kernel to attempt to access an unmapped page and subsequently panic.

Improper bounds checking of the obuf variable in the linkntoa() function in linkaddr.c of the BSD libc library may allow an attacker to read or write from memory. The full impact and severity depends on the method of exploit and how the library is used by applications. According to analysis by FreeBSD developers, it is very unlikely that applications exist that utilize linkntoa() in an exploitable manner, and the CERT/CC is not aware of any proof of concept. A blog post describes the functionality of linkntoa() and points out that none of the base utilities use this function in an exploitable manner. For more information, please see FreeBSD Security Advisory SA-16:37.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of FreeBSD Kernel. Authentication is not required to exploit this vulnerability. The specific flaw exists within the implementation of NAT. The issue results from the lack of proper validation of user-supplied data, which can result in a memory access past the end of an allocated buffer. An attacker can leverage this vulnerability to execute code in the context of kernel.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of FreeBSD Kernel. Authentication is not required to exploit this vulnerability. The specific flaw exists within the implementation of NAT. The issue results from the lack of proper validation of user-supplied data, which can result in a memory access past the end of an allocated buffer. An attacker can leverage this vulnerability to execute code in the context of kernel.

In FreeBSD 12.1-STABLE before r360971, 12.1-RELEASE before p5, 11.4-STABLE before r360971, 11.4-BETA1 before p1 and 11.3-RELEASE before p9, libalias does not properly validate packet length resulting in modules causing an out of bounds read/write condition if no checking was built into the module.

In FreeBSD 12.1-STABLE before r356035, 12.1-RELEASE before 12.1-RELEASE-p4, 11.3-STABLE before r356036, and 11.3-RELEASE before 11.3-RELEASE-p8, incomplete packet data validation may result in memory access after it has been freed leading to a kernel panic or other unpredictable results.

In FreeBSD 12.1-STABLE before r356035, 12.1-RELEASE before 12.1-RELEASE-p4, 11.3-STABLE before r356036, and 11.3-RELEASE before 11.3-RELEASE-p8, incomplete packet data validation may result in accessing out-of-bounds memory leading to a kernel panic or other unpredictable results.

In FreeBSD 12.1-STABLE before r362281, 11.4-STABLE before r362281, and 11.4-RELEASE before p1, long values in the user-controlled PATH environment variable cause posixspawnp to write beyond the end of the heap allocated stack possibly leading to arbitrary code execution.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of FreeBSD Kernel. Authentication is not required to exploit this vulnerability. The specific flaw exists within the implementation of NAT. The issue results from the lack of proper validation of user-supplied data, which can result in a memory access past the end of an allocated buffer. An attacker can leverage this vulnerability to execute code in the context of kernel.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of FreeBSD Kernel. Authentication is not required to exploit this vulnerability. The specific flaw exists within the implementation of NAT. The issue results from the lack of proper validation of user-supplied data, which can result in a memory access past the end of an allocated buffer. An attacker can leverage this vulnerability to execute code in the context of kernel.

AnyDesk before 5.5.3 on Linux and FreeBSD has a format string vulnerability that can be exploited for remote code execution.

In FreeBSD 12.1-STABLE before r356911, and 12.1-RELEASE before p5, insufficient checking in the cryptodev module allocated the size of a kernel buffer based on a user-supplied length allowing an unprivileged process to trigger a kernel panic.

In FreeBSD 12.0-RELEASE before 12.0-RELEASE-p13, a missing check in the ipsec packet processor allows reinjection of an old packet to be accepted by the ipsec endpoint. Depending on the higher-level protocol in use over ipsec, this could allow an action to be repeated.

OpenPAM Nummularia 9.2 through 10.0 does not properly handle the error reported when an include directive refers to a policy that does not exist, which causes the loaded policy chain to no be discarded and allows context-dependent attackers to bypass authentication via a login (1) without a password or (2) with an incorrect password.

In FreeBSD 12.0-STABLE before r349622, 12.0-RELEASE before 12.0-RELEASE-p7, 11.3-PRERELEASE before r349624, 11.3-RC3 before 11.3-RC3-p1, and 11.2-RELEASE before 11.2-RELEASE-p11, a bug in iconv implementation may allow an attacker to write past the end of an output buffer. Depending on the implementation, an attacker may be able to create a denial of service, provoke incorrect program behavior, or induce a remote code execution.

In FreeBSD before 11.2-STABLE(r348229), 11.2-RELEASE-p7, 12.0-STABLE(r342228), and 12.0-RELEASE-p1, insufficient validation of network-provided data in bootpd may make it possible for a malicious attacker to craft a bootp packet which could cause a stack buffer overflow. It is possible that the buffer overflow could lead to a Denial of Service or remote code execution.

In versions of FreeBSD 12.4-RELEASE prior to 12.4-RELEASE-p7 and FreeBSD 13.2-RELEASE prior to 13.2-RELEASE-p5 the sflush() stdio function in libc does not correctly update FILE objects' write space members for write-buffered streams when the write(2) system call returns an error.  Depending on the nature of an application that calls libc's stdio functions and the presence of errors returned from the write(2) system call (or an overridden stdio write routine) a heap buffer overflow may occur. Such overflows may lead to data corruption or the execution of arbitrary code at the privilege level of the calling program.

In FreeBSD 12.0-STABLE before r350246, 12.0-RELEASE before 12.0-RELEASE-p8, 11.3-STABLE before r350247, 11.3-RELEASE before 11.3-RELEASE-p1, and 11.2-RELEASE before 11.2-RELEASE-p12, the emulated XHCI device included with the bhyve hypervisor did not properly validate data provided by the guest, allowing an out-of-bounds read. This provides a malicious guest the possibility to crash the system or access system memory.

BSD compress implemented an LZW compressor and decompressor. This decompressor implementation did not correctly handle compressed streams that contain code words that were not yet added to the decompression table. LZW decompression has a special case (a KwKwK string) when code word may match the first free entry in the decompression table. The implementation used in BSD compress allow code words not only matching, but also exceeding the first free entry.

It seems this compress implementation first appeared in BSD around 1985, and was later used in various other code base, such as ncompress and gzip. Other components that contain affected code will be listed below. Following page list the version of the code as was used in 4.3BSD:

http://minnie.tuhs.org/cgi-bin/utree.pl?file=4.3BSD-Reno/src/usr.bin/compress/compress.c

Relevant code appears in the decompress() routine:

/ Special case for KwKwK string. / if ( code >= freeent ) { stackp++ = finchar; code = oldcode; }

This allows creating a loop in the decompression table, which leads to an "infinite" loop:

/ Generate output characters in reverse order / #ifdef SIGNEDCOMPARESLOW while ( ((unsigned long)code) >= ((unsigned long)256) ) { #else while ( code >= 256 ) { #endif stackp++ = tabsuffixof(code); code = tabprefixof(code); }

where tabprefixof is:

unsigned short codetab [HSIZE]; #define codetabof(i) codetab[i] #define tabprefixof(i) codetabof(i)

This overflows destack "buffer" (part of the htab[]):

countint htab [HSIZE]; # define tabsuffixof(i) ((chartype )(htab))[i] # define destack ((chartype )&tabsuffixof(1<<BITS))

Depending on the relative htab[] and codetab[] positions, destack overflow may overwrite codetab[] entries, which may break infinite loop and let program continue its execution with possibly corrupted memory.