OpenBSD vulnerabilities
We track 21 vulnerabilities in OpenBSD products across 4 products. 21 are rated high or critical, and 2 have been exploited in real attacks. The most recent was published on November 5, 2026.
Latest OpenBSD vulnerabilities
- 8.1 High severity
OpenBSD OpenSSH Unexpected Status Code or Return Value Exploited
sshd in OpenSSH before 10.6p2 on Linux, when musl libc is used without PAM, lacks a workaround for a password authentication bypass (related to misinterpretation of whether a string is intended to be a password hash). For some configurations of accounts, any p
- 9.2 Critical severity
OpenBSD: Incorrect Authorization
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 sa
- 9.4 Critical severity
OpenSSH: Use After Free
ssh in OpenSSH before 10.4 can have a use-after-free when a server changes its host key during a key re-exchange. (This outcome occurs only on the client side.)
- 7.5 High severity
OpenSSH: Allocation of Resources Without Limits or Throttling
sshd in OpenSSH before 10.4 allows remote attackers to cause a denial of service (resource consumption from excessive authentication attempts) because MaxAuthTries was mishandled for GSSAPIAuthentication.
- 7.8 High severity
OpenBSD: Use After Free
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().
- 8.1 High severity
OpenSSH: Always-Incorrect Control Flow Implementation
OpenSSH before 10.3 mishandles the authorized_keys principals option in uncommon scenarios involving a principals list in conjunction with a Certificate Authority that makes certain use of comma characters.
- 8.1 High severity
OpenSSH: Incorrect Behavior Order
In OpenSSH before 10.3, command execution can occur via shell metacharacters in a username within a command line. This requires a scenario where the username on the command line is untrusted, and also requires a non-default configurations of % in ssh_config.
- 8.1 High severity
OpenSSH: Improper Preservation of Permissions
In OpenSSH before 10.3, a file downloaded by scp may be installed setuid or setgid, an outcome contrary to some users' expectations, if the download is performed as root with -O (legacy scp protocol) and without -p (preserve mode).
- 7.5 High severity
OpenBSD: NULL Pointer Dereference
In OpenBSD 7.4 before errata 006 and OpenBSD 7.3 before errata 020, httpd(8) is vulnerable to a NULL dereference when handling a malformed fastcgi request.
- 9.8 Critical severity
OpenBSD: Double Free
In OpenBSD 7.5 before errata 008 and OpenBSD 7.4 before errata 021, avoid possible mbuf double free in NFS client and server implementation, do not use uninitialized variable in error handling of NFS server.
- 7.3 High severity
cron: Out-of-bounds Write
cron/entry.c in vixie cron before 9cc8ab1, as used in OpenBSD 7.4 and 7.5, allows a heap-based buffer underflow and memory corruption. NOTE: this issue was introduced during a May 2023 refactoring.
- 7.5 High severity
openssh: Time-of-check Time-of-use (TOCTOU) Race Condition
OpenSSH 9.5 through 9.7 before 9.8 sometimes allows timing attacks against echo-off password entry (e.g., for su and Sudo) because of an ObscureKeystrokeTiming logic error. Similarly, other timing attacks against keystroke entry could occur.
- 8.1 High severity
Red Hat Enterprise Linux 9: Concurrent Execution using Shared Resource with Improper Synchronization
A security regression (CVE-2006-5051) was discovered in OpenSSH's server (sshd). There is a race condition which can lead sshd to handle some signals in an unsafe manner. An unauthenticated, remote attacker may be able to trigger it by failing to authenticate
- 9.8 Critical severity
openbsd: Improper Control of Generation of Code
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.
- 7.5 High severity
OpenBSD: Incorrect Calculation of Buffer Size
In OpenBSD 7.4 before errata 002 and OpenBSD 7.3 before errata 019, a network buffer that had to be split at certain length that could crash the kernel after receiving specially crafted escape sequences.
- 9.8 Critical severity
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: Unquoted Search Path or Element
The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently trustworthy search path, leading to remote code execution if an agent is forwarded to an attacker-controlled system. (Code in /usr/lib is not necessarily safe for loading into ssh-a
- 9.8 Critical severity
Libressl: Double Free
A double free or use after free could occur after SSL_clear in OpenBSD 7.2 before errata 026 and 7.3 before errata 004, and in LibreSSL before 3.6.3 and 3.7.x before 3.7.3. NOTE: OpenSSL is not affected.
- 9.8 Critical severity
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP…: Improper Access Control
ssh-add in OpenSSH before 9.3 adds smartcard keys to ssh-agent without the intended per-hop destination constraints. The earliest affected version is 8.9.
- 7.5 High severity
Openbsd: Incorrect Conversion between Numeric Types
slaacd in OpenBSD 6.9 and 7.0 before 2022-03-22 has an integer signedness error and resultant heap-based buffer overflow triggerable by a crafted IPv6 router advertisement. NOTE: privilege separation and pledge can prevent exploitation.
- 7.5 High severity
Openbsd: Buffer Copy without Checking Size of Input
engine.c in slaacd in OpenBSD 6.9 and 7.0 before 2022-02-21 has a buffer overflow triggerable by an IPv6 router advertisement with more than seven nameservers. NOTE: privilege separation and pledge can prevent exploitation.
- 9.8 Critical severity
OpenSMTPD Remote Code Execution Exploited
smtp_mailaddr in smtp_session.c in OpenSMTPD 6.6, as used in OpenBSD 6.6 and other products, allows remote attackers to execute arbitrary commands as root via a crafted SMTP session, as demonstrated by shell metacharacters in a MAIL FROM field. This affects th