OpenSSH

The client side in OpenSSH 5.7 through 8.4 has an Observable Discrepancy leading to an information leak in the algorithm negotiation. This allows man-in-the-middle attackers to target initial connection attempts (where no host key for the server has been cached by the client).…

An issue was discovered in OpenSSH 7.9. Due to the scp implementation being derived from 1983 rcp, the server chooses which files/directories are sent to the client. However, the scp client only performs cursory validation of the object name returned (only directory traversal…

An issue was discovered in OpenSSH 7.9. Due to missing character encoding in the progress display, a malicious server (or Man-in-The-Middle attacker) can employ crafted object names to manipulate the client output, e.g., by using ANSI control codes to hide additional files being…

In ssh-agent in OpenSSH before 9.6, certain destination constraints can be incompletely applied. When destination constraints are specified during addition of PKCS#11-hosted private keys, these constraints are only applied to the first key, even if a PKCS#11 token returns…

The ssh_packet_read_poll2 function in packet.c in OpenSSH before 7.1p2 allows remote attackers to cause a denial of service (out-of-bounds read and application crash) via crafted network traffic.

ssh-keysign.c in ssh-keysign in OpenSSH before 5.8p2 on certain platforms executes ssh-rand-helper with unintended open file descriptors, which allows local users to obtain sensitive key information via the ptrace system call.

sshd in OpenSSH before 10.4 does not always honor the minimum authentication delay.

In OpenSSH 7.9, scp.c in the scp client allows remote SSH servers to bypass intended access restrictions via the filename of . or an empty filename. The impact is modifying the permissions of the target directory on the client side.

The process_open function in sftp-server.c in OpenSSH before 7.6 does not properly prevent write operations in readonly mode, which allows attackers to create zero-length files.

The monitor component in sshd in OpenSSH before 7.0 on non-OpenBSD platforms accepts extraneous username data in MONITOR_REQ_PAM_INIT_CTX requests, which allows local users to conduct impersonation attacks by leveraging any SSH login access in conjunction with control of the…

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…

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 ssh in OpenSSH before 10.5, a use-after-free for realloc data can occur if a certain pair of remote-forwarding operations are concurrent.

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

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…

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…

In sshd in OpenSSH before 10.0, the DisableForwarding directive does not adhere to the documentation stating that it disables X11 and agent forwarding.

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.

In sftp in OpenSSH before 10.6, a server can trigger directory traversal (causing files to be written to unintended locations) during a recursive copy operation.

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.

In sshd and ssh in OpenSSH before 10.6, an LZ77 dictionary coder can be used even though this is contraindicated by the arXiv 2609.07709 "Crossing the Streams" findings.

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 sshd in OpenSSH before 10.6, the value "none" for a configuration option is sometimes interpreted as a filename but was intended to mean that a feature is disabled.

In ssh-agent in OpenSSH before 10.5, some operations can occur remotely but were intended to occur only locally, including operations that add tokens or use keys. This is caused by misinteraction between agent locking and the [email protected] extension.

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.

ssh in OpenSSH before 10.1 allows the '\0' character in an ssh:// URI, potentially leading to code execution when a ProxyCommand is used.

ssh in OpenSSH before 10.1 allows control characters in usernames that originate from certain possibly untrusted sources, potentially leading to code execution when a ProxyCommand is used. The untrusted sources are the command line and %-sequence expansion of a configuration…

In sshd in OpenSSH through 10.6, use of the macOS 27 (or later) SDK has the side effect of loss of sandboxing, which is potentially unexpected.

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.

In sshd in OpenSSH through 10.6, in certain environments such as QNX 6 and SCO OpenServer 5, sshd-session can unexpectedly have root privileges. This is related to the GatewayPorts and StreamLocalForwarding configuration options, and lack of support for file-descriptor passing…

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.

In ssh in OpenSSH before 10.6, a $ or \ character can occur in a command-line username, leading to injection.

In sshd in OpenSSH before 10.6, the restrict keyword (in authorized_keys) was supposed to be applicable to tunnel forwarding but was not, a different vulnerability than CVE-2026-73283.

In ssh-keygen in OpenSSH before 10.6, certificates could have incorrect expiration times because of Daylight Saving mishandling. There can be a slightly more severe effect on users in certain Antarctic locations.

In sshd in OpenSSH before 10.5, the restrict keyword (in authorized_keys) was supposed to be applicable to tunnel forwarding but was not.

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

In sshd in OpenSSH before 10.6, GSSAPIAuthentication authentication state can incorrectly be persisted across authentication attempts.

In sshd in OpenSSH before 10.6, credentials can incorrectly persist after failure of a GSSAPIAuthentication authentication attempt.

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.

sshd in OpenSSH 4 on Debian GNU/Linux, and the 20070303 OpenSSH snapshot, allows remote authenticated users to obtain access to arbitrary SELinux roles by appending a :/ (colon slash) sequence, followed by the role name, to the username.

The (1) remote_glob function in sftp-glob.c and the (2) process_put function in sftp.c in OpenSSH 5.8 and earlier, as used in FreeBSD 7.3 and 8.1, NetBSD 5.0.2, OpenBSD 4.7, and other products, allow remote authenticated users to cause a denial of service (CPU and memory…

Rejected reason: CVE-2026-110923 has been marked as a duplicate of CVE-2026-106552.

The OpenSSH server, as used in Fedora and Red Hat Enterprise Linux 7 and when running in a Kerberos environment, allows remote authenticated users to log in as another user when they are listed in the .k5users file of that user, which might bypass intended authentication…

The ssh_gssapi_parse_ename function in gss-serv.c in OpenSSH 5.8 and earlier, when gssapi-with-mic authentication is enabled, allows remote authenticated users to cause a denial of service (memory consumption) via a large value in a certain length field. NOTE: there may be…