In OpenBGPD before 8.1, incorrect handling of BGP update data (length of path attributes) set by a potentially distant remote actor may cause the system to incorrectly reset a session. This is fixed in OpenBSD 7.3 errata 006.
x509/x509_verify.c in LibreSSL before 3.4.2, and OpenBSD before 7.0 errata 006, allows authentication bypass because an error for an unverified certificate chain is sometimes discarded.
An issue was discovered in x509/x509_verify.c in LibreSSL before 3.6.1, and in OpenBSD before 7.2 errata 001. x509_verify_ctx_add_chain does not store errors that occur during leaf certificate verification, and therefore an incorrect error is returned. This behavior occurs when there is an installed verification callback that instructs the verifier to continue upon detecting an invalid certificate.
iked in OpenIKED, as used in OpenBSD through 6.7, allows authentication bypass because ca.c has the wrong logic for checking whether a public key matches.
OpenBSD through 6.6 allows local users to escalate to root because a check for LD_LIBRARY_PATH in setuid programs can be defeated by setting a very small RLIMIT_DATA resource limit. When executing chpass or passwd (which are setuid root), _dl_setup_env in ld.so tries to strip LD_LIBRARY_PATH from the environment, but fails when it cannot allocate memory. Thus, the attacker is able to execute their own library code as root.
OpenBSD kernel version <= 6.5 can be forced to create long chains of TCP SACK holes that causes very expensive calls to tcp_sack_option() for every incoming SACK packet which can lead to a denial of service.
A flaw exists in OpenBSD's implementation of the stack guard page that allows attackers to bypass it resulting in arbitrary code execution using setuid binaries such as /usr/bin/at. This affects OpenBSD 6.1 and possibly earlier versions.
The OpenBSD qsort() function is recursive, and not randomized, an attacker can construct a pathological input array of N elements that causes qsort() to deterministically recurse N/4 times. This allows attackers to consume arbitrary amounts of stack memory and manipulate stack memory to assist in arbitrary code execution attacks. This affects OpenBSD 6.1 and possibly earlier versions.
The TCP stack in 4.3BSD Net/2, as used in FreeBSD 5.4, NetBSD possibly 2.0, and OpenBSD possibly 3.6, does not properly implement the session timer, which allows remote attackers to cause a denial of service (resource consumption) via crafted packets.
The LZW decompressor in (1) the BufCompressedFill function in fontfile/decompress.c in X.Org libXfont before 1.4.4 and (2) compress/compress.c in 4.3BSD, as used in zopen.c in OpenBSD before 3.8, FreeBSD, NetBSD 4.0.x and 5.0.x before 5.0.3 and 5.1.x before 5.1.1, FreeType 2.1.9, and other products, does not properly handle code words that are absent from the decompression table when encountered, which allows context-dependent attackers to trigger an infinite loop or a heap-based buffer overflow, and possibly execute arbitrary code, via a crafted compressed stream, a related issue to CVE-2006-1168 and CVE-2011-2896.