OpenBSD ieee80211_crypto_tkip.c TKIP MIC Countermeasure Logic Inversion DoS

OpenBSD before commit 1ee99df contains an inverted comparison vulnerability in the ieee80211_michael_mic_failure() function within sys/net80211/ieee80211_crypto_tkip.c that allows unauthenticated attackers within RF range to trigger denial of service by sending two malformed TKIP frames separated by more than 60 seconds. Attackers can exploit the reversed TKIP MIC failure countermeasure window check to deauthenticate all associated TKIP stations and block reassociation for up to 90 seconds, while within-window MIC failures that should engage countermeasures are silently discarded, leaving key-recovery attempts undetected.

LDAP Authentication Bypass via Reused File Descriptor and Message ID in OpenBSD ldapd

In ldapd in OpenBSD 7.8 before errata 057 and 7.9 before errata 021, delegated BSD authentication results are correlated only by the LDAP child process client file descriptor and LDAP message ID. After a connection closes, a later connection that reuses the same file descriptor and message ID can receive the earlier authentication result. A remote attacker who can reach ldapd can complete a Bind as another identity. A missing connection can also cause a NULL pointer dereference. (ldapd is not enabled by default.)

OpenBSD Kernel Use‑After‑Free Enables Local Privilege Escalation

sys/kern/sysv_sem.c in OpenBSD through 7.9 has a use-after-free allowing local privilege escalation to root. This is a context switch use-after-free after tsleep in sys_semget().

OpenBSD mpls_do_error Kernel Stack Memory Disclosure via MPLS Input

OpenBSD before commit 6a23123 (2026-06-18) contains an out-of-bounds read vulnerability in the mpls_do_error function within sys/netmpls/mpls_input.c that allows remote attackers to disclose kernel stack memory by sending crafted MPLS frames with 16 labels and no Bottom-of-Stack bit set.

Authentication Bypass via Zero-Length Input in sppp_pap

sppp_pap_input in sys/net/if_spppsubr.c in OpenBSD before 076e2b1 allows authentication bypass via certain zero values for lengths.

In OpenBSD through 7.8, the slaacd and rad daemons have an infinite loop when they receive a crafted ICMPv6 Neighbor Discovery (ND) option (over a local network) with length zero, because of an "nd_opt_len * 8 - 2" expression with no preceding check for whether nd_opt_len is zero.

A certain pseudo-random number generator (PRNG) algorithm that uses XOR and 3-bit random hops (aka "Algorithm X3"), as used in OpenBSD 2.8 through 4.2, allows remote attackers to guess sensitive values such as DNS transaction IDs by observing a sequence of previously generated values. NOTE: this issue can be leveraged for attacks such as DNS cache poisoning against OpenBSD's modification of BIND.

OpenBSD 4.2 allows local users to cause a denial of service (kernel panic) by calling the SIOCGIFRTLABEL IOCTL on an interface that does not have a route label, which triggers a NULL pointer dereference when the return value from the rtlabel_id2name function is not checked.

A certain pseudo-random number generator (PRNG) algorithm that uses XOR and 2-bit random hops (aka "Algorithm X2"), as used in OpenBSD 2.6 through 3.4, Mac OS X 10 through 10.5.1, FreeBSD 4.4 through 7.0, and DragonFlyBSD 1.0 through 1.10.1, allows remote attackers to guess sensitive values such as IP fragmentation IDs by observing a sequence of previously generated values. NOTE: this issue can be leveraged for attacks such as injection into TCP packets and OS fingerprinting.

Buffer overflow in kern/uipc_mbuf2.c in OpenBSD 3.9 and 4.0 allows remote attackers to execute arbitrary code via fragmented IPv6 packets due to "incorrect mbuf handling for ICMP6 packets." NOTE: this was originally reported as a denial of service.

dhcpd stack-based buffer overlow

Stack-based buffer overflow in the cons_options function in options.c in dhcpd in OpenBSD 4.0 through 4.2, and some other dhcpd implementations based on ISC dhcp-2, allows remote attackers to execute arbitrary code or cause a denial of service (daemon crash) via a DHCP request specifying a maximum message size smaller than the minimum IP MTU.

Cross-site scripting (XSS) vulnerability in cgi-bin/bgplg in the web interface for the BGPD daemon in OpenBSD 4.1 allows remote attackers to inject arbitrary web script or HTML via the cmd parameter.

The ip6_check_rh0hdr function in netinet6/ip6_input.c in OpenBSD 4.2 allows attackers to cause a denial of service (panic) via malformed IPv6 routing headers.

The tcp_respond function in netinet/tcp_subr.c in OpenBSD 4.1 and 4.2 allows attackers to cause a denial of service (panic) via crafted TCP packets. NOTE: some of these details are obtained from third party information.

Multiple font integer overflows (CVE-2007-1352)

Integer overflow in the FontFileInitTable function in X.Org libXfont before 20070403 allows remote authenticated users to execute arbitrary code via a long first line in the fonts.dir file, which results in a heap overflow.

IPv6 routing headers issue

The IPv6 protocol allows remote attackers to cause a denial of service via crafted IPv6 type 0 route headers (IPV6_RTHDR_TYPE_0) that create network amplification between two routers.

OpenBSD and NetBSD permit usermode code to kill the display server and write to the X.Org /dev/xf86 device, which allows local users with root privileges to reduce securelevel by replacing the System Management Mode (SMM) handler via a write to an SMRAM address within /dev/xf86 (aka the video card memory-mapped I/O range), and then launching the new handler via a System Management Interrupt (SMI), as demonstrated by a write to Programmed I/O port 0xB2.

Integer overflow in banner/banner.c in FreeBSD, NetBSD, and OpenBSD might allow local users to modify memory via a long banner. NOTE: CVE and multiple third parties dispute this issue. Since banner is not setuid, an exploit would not cross privilege boundaries in normal operations. This issue is not a vulnerability

Multiple font integer overflows (CVE-2007-1352)

Integer overflow in the bdfReadCharacters function in bdfread.c in (1) X.Org libXfont before 20070403 and (2) freetype 2.3.2 and earlier allows remote authenticated users to execute arbitrary code via crafted BDF fonts, which result in a heap overflow.

Unspecified vulnerability in sys/dev/pci/vga_pci.c in the VGA graphics driver for wscons in OpenBSD 3.9 and 4.0, when the kernel is compiled with the PCIAGP option and a non-AGP device is being used, allows local users to gain privileges via unspecified vectors, possibly related to agp_ioctl NULL pointer reference.