OpenBSD

A flaw was found in OpenSSH. A local unprivileged attacker on a Linux client host can hijack client-side X11 forwarding connections. This is possible by pre-binding the preferred abstract X socket name when X11 forwarding is enabled and a local UNIX-domain X socket is used. A…

In OpenBSD 7.5 before errata 009 and OpenBSD 7.4 before errata 022, exclude any '/' in readdir name validation to avoid unexpected directory traversal on untrusted file systems.

authfile.c in sshd in OpenSSH before 7.4 does not properly consider the effects of realloc on buffer contents, which might allow local users to obtain sensitive private-key information by leveraging access to a privilege-separated child process.

In sshd in OpenSSH before 10.4, DisableForwarding=yes was supposed to take precedence over PermitTunnel=yes, but did not.

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

LibreSSL before 2.6.5 and 2.7.x before 2.7.4 allows a memory-cache side-channel attack on DSA and ECDSA signatures, aka the Return Of the Hidden Number Problem or ROHNP. To discover a key, the attacker needs access to either the local machine or a different virtual machine on…

An Improper Check for Unusual or Exceptional Conditions vulnerability in OpenSMTPD allows local users to crash OpenSMTPD. This issue affects openSUSE Tumbleweed: from ? before 7.8.0p0-1.1.

OpenBSD 5.8 and 5.9 allows certain local users with kern.usermount privileges to cause a denial of service (kernel panic) by mounting a tmpfs with a VNOVAL in the (1) username, (2) groupname, or (3) device name of the root node.

A flaw was found in OpenSSH. A malicious SSH server can exploit a double free vulnerability in the Diffie-Hellman Group Exchange (DH-GEX) client path. This occurs during FIPS (Federal Information Processing Standards) mode known-group validation when the client processes…

OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. This occurs because a challenge is sent only when that combination could be valid for a…

sshd in OpenSSH before 6.6 does not properly support wildcards on AcceptEnv lines in sshd_config, which allows remote attackers to bypass intended environment restrictions by using a substring located before a wildcard character.

Error handling in the SSH protocol in (1) SSH Tectia Client and Server and Connector 4.0 through 4.4.11, 5.0 through 5.2.4, and 5.3 through 5.3.8; Client and Server and ConnectSecure 6.0 through 6.0.4; Server for Linux on IBM System z 6.0.4; Server for IBM z/OS 5.5.1 and…

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…

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.

sshd in OpenSSH before 10.4 has an undocumented security-relevant behavior: GSSAPIStrictAcceptorCheck has no value if the server is in Windows Active Directory.

A flaw was found in OpenSSH. This vulnerability, a heap out-of-bounds read, occurs during the cleanup of GSSAPI (Generic Security Service Application Programming Interface) indicators when a trailing NULL termination is missing in the auth-indicators array. A remote attacker,…

An issue was discovered in OpenSSH before 8.9. If a client is using public-key authentication with agent forwarding but without -oLogLevel=verbose, and an attacker has silently modified the server to support the None authentication option, then the user cannot determine whether…

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.

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 the "uncommented"…

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…

OpenBSD Kernel Multicast Routing Uninitialized Memory Information Disclosure Vulnerability. This vulnerability allows local attackers to disclose sensitive information on affected installations of OpenBSD Kernel. An attacker must first obtain the ability to execute…

internal-sftp in sshd in OpenSSH before 10.4 recognizes only the first 9 command-line arguments, which can be important if a later command-line argument would have helped to ensure the intended security properties of an SFTP connection.

scp in OpenSSH before 10.4 may place a file in the parent directory of an intended directory when the copy occurs between two remote destinations.

sftp in OpenSSH before 10.4 does not properly constrain the location of downloaded files when "sftp server:/path ." is used with an attacker-controlled server.

OpenSSH before 10.3 can use unintended ECDSA algorithms. Listing of any ECDSA algorithm in PubkeyAcceptedAlgorithms or HostbasedAcceptedAlgorithms is misinterpreted to mean all ECDSA algorithms.

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.

OpenSSH before 10.3 omits connection multiplexing confirmation for proxy-mode multiplexing sessions.

Multiple TCP implementations with Protection Against Wrapped Sequence Numbers (PAWS) with the timestamps option enabled allow remote attackers to cause a denial of service (connection loss) via a spoofed packet with a large timer value, which causes the host to discard later…

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…

OpenSSH-portable (OpenSSH) 3.6.1p1 and earlier with PAM support enabled immediately sends an error message when a user does not exist, which allows remote attackers to determine valid usernames via a timing attack.

FTP servers such as OpenBSD ftpd, NetBSD ftpd, ProFTPd and Opieftpd do not properly cleanse untrusted format strings that are used in the setproctitle function (sometimes called by set_proc_title), which allows remote attackers to cause a denial of service or execute arbitrary…

OpenSSH portable 4.1 on SUSE Linux, and possibly other platforms and versions, and possibly under limited configurations, allows remote attackers to determine valid usernames via timing discrepancies in which responses take longer for valid usernames than invalid ones, as…

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-agent.) NOTE: this…

sshd in OpenSSH before 4.4, when using the version 1 SSH protocol, allows remote attackers to cause a denial of service (CPU consumption) via an SSH packet that contains duplicate blocks, which is not properly handled by the CRC compensation attack detector.

Buffer overflow in BSD-based telnetd telnet daemon on various operating systems allows remote attackers to execute arbitrary commands via a set of options including AYT (Are You There), which is not properly handled by the telrcv function.

CORE SDI SSH1 CRC-32 compensation attack detector allows remote attackers to execute arbitrary commands on an SSH server or client via an integer overflow.

Stack consumption vulnerability in the fnmatch implementation in apr_fnmatch.c in the Apache Portable Runtime (APR) library before 1.4.3 and the Apache HTTP Server before 2.2.18, and in fnmatch.c in libc in NetBSD 5.1, OpenBSD 4.8, FreeBSD, Apple Mac OS X 10.6, Oracle Solaris…

Array index error in the (1) dtoa implementation in dtoa.c (aka pdtoa.c) and the (2) gdtoa (aka new dtoa) implementation in gdtoa/misc.c in libc, as used in multiple operating systems and products including in FreeBSD 6.4 and 7.2, NetBSD 5.0, OpenBSD 4.5, Mozilla Firefox 3.0.x…

Buffer overflow in ReadFontAlias from dirfile.c of XFree86 4.1.0 through 4.3.0 allows local users and remote attackers to execute arbitrary code via a font alias file (font.alias) with a long token, a different vulnerability than CVE-2004-0084 and CVE-2004-0106.

Buffer overflow in the ReadFontAlias function in XFree86 4.1.0 to 4.3.0, when using the CopyISOLatin1Lowered function, allows local or remote authenticated users to execute arbitrary code via a malformed entry in the font alias (font.alias) file, a different vulnerability than…

A "potential buffer overflow in ruleset parsing" for Sendmail 8.12.9, when using the nonstandard rulesets (1) recipient (2), final, or (3) mailer-specific envelope recipients, has unknown consequences.

Buffer overflows in BSD-based FTP servers allows remote attackers to execute arbitrary commands via a long pattern string containing a {} sequence, as seen in (1) g_opendir, (2) g_lstat, (3) g_stat, and (4) the glob0 buffer as used in the glob functions glob2 and glob3.

The pf_test_rule function in OpenBSD Packet Filter (PF), as used in OpenBSD 4.2 through 4.5, NetBSD 5.0 before RC3, MirOS 10 and earlier, and MidnightBSD 0.3-current allows remote attackers to cause a denial of service (panic) via crafted IP packets that trigger a NULL pointer…

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.

Format string vulnerability in wrapper.c in CVS 1.12.x through 1.12.8, and 1.11.x through 1.11.16 allows remote attackers with CVSROOT commit access to cause a denial of service (application crash) and possibly execute arbitrary code via format string specifiers in a wrapper…

Double free vulnerability for the error_prog_name string in CVS 1.12.x through 1.12.8, and 1.11.x through 1.11.16, may allow remote attackers to execute arbitrary code.

ssl3_get_record in s3_pkt.c for OpenSSL before 0.9.7a and 0.9.6 before 0.9.6i does not perform a MAC computation if an incorrect block cipher padding is used, which causes an information leak (timing discrepancy) that may make it easier to launch cryptographic attacks that rely…

BIND 8.3.x through 8.3.3 allows remote attackers to cause a denial of service (termination due to assertion failure) via a request for a subdomain that does not exist, with an OPT resource record with a large UDP payload size.

One-byte buffer overflow in replydirname function in BSD-based ftpd allows remote attackers to gain root privileges.

sshd in OpenSSH 6.8 and 6.9 uses world-writable permissions for TTY devices, which allows local users to cause a denial of service (terminal disruption) or possibly have unspecified other impact by writing to a device, as demonstrated by writing an escape sequence.