In FreeBSD 12.0-STABLE before r350222, 12.0-RELEASE before 12.0-RELEASE-p8, 11.3-STABLE before r350223, 11.3-RELEASE before 11.3-RELEASE-p1, and 11.2-RELEASE before 11.2-RELEASE-p12, rights transmitted over a domain socket did not properly release a reference on transmission error allowing a malicious user to cause the reference counter to wrap, forcing a free event. This could allow a malicious local user to gain root privileges or escape from a jail.

In FreeBSD 12.0-STABLE before r349805, 12.0-RELEASE before 12.0-RELEASE-p8, 11.3-STABLE before r349806, 11.3-RELEASE before 11.3-RELEASE-p1, and 11.2-RELEASE before 11.2-RELEASE-p12, code which handles close of a descriptor created by posix_openpt fails to undo a signal configuration. This causes an incorrect signal to be raised leading to a write after free of kernel memory allowing a malicious user to gain root privileges or escape a jail.

In FreeBSD 11.3-STABLE before r350217, 11.3-RELEASE before 11.3-RELEASE-p1, and 11.2-RELEASE before 11.2-RELEASE-p12, due to insufficient initialization of memory copied to userland in the freebsd32_ioctl interface, small amounts of kernel memory may be disclosed to userland processes. This may allow an attacker to leverage this information to obtain elevated privileges either directly or indirectly.

In FreeBSD 12.0-STABLE before r350261, 12.0-RELEASE before 12.0-RELEASE-p8, 11.3-STABLE before r350263, 11.3-RELEASE before 11.3-RELEASE-p1, and 11.2-RELEASE before 11.2-RELEASE-p12, system calls operating on file descriptors as part of mqueuefs did not properly release the reference allowing a malicious user to overflow the counter allowing access to files, directories, and sockets opened by processes owned by other users.

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.

In FreeBSD 12.0-STABLE before r349628, 12.0-RELEASE before 12.0-RELEASE-p7, 11.3-PRERELEASE before r349629, 11.3-RC3 before 11.3-RC3-p1, and 11.2-RELEASE before 11.2-RELEASE-p11, a bug in the cdrom driver allows users with read access to the cdrom device to arbitrarily overwrite kernel memory when media is present thereby allowing a malicious user in the operator group to gain root privileges.

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.

BZ2_decompress in decompress.c in bzip2 through 1.0.6 has an out-of-bounds write when there are many selectors.

The RFC 5011 implementation in rdata.c in ISC BIND 9.7.x and 9.8.x before 9.8.5-P2, 9.8.6b1, 9.9.x before 9.9.3-P2, and 9.9.4b1, and DNSco BIND 9.9.3-S1 before 9.9.3-S1-P1 and 9.9.4-S1b1, allows remote attackers to cause a denial of service (assertion failure and named daemon exit) via a query with a malformed RDATA section that is not properly handled during construction of a log message, as exploited in the wild in July 2013.

Buffer overflow in libtelnet/encrypt.c in telnetd in FreeBSD 7.3 through 9.0, MIT Kerberos Version 5 Applications (aka krb5-appl) 1.0.2 and earlier, Heimdal 1.5.1 and earlier, GNU inetutils, and possibly other products allows remote attackers to execute arbitrary code via a long encryption key, as exploited in the wild in December 2011.