A system is running a version of software that was replaced with a Trojan Horse at one of its distribution points, such as (1) TCP Wrappers 7.6, (2) util-linux 2.9g, (3) wuarchive ftpd (wuftpd) 2.2 and 2.1f, (4) IRC client (ircII) ircII 2.2.9, (5) OpenSSH 3.4p1, or (6) Sendmail 8.12.6.

Last updated 13 July 2026

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

Last updated 22 September 2026

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

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

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

On July 1, 2024, the Qualys Threat Research Unit (TRU) disclosed an unauthenticated, remote code execution vulnerability that affects the OpenSSH server (sshd) in glibc-based Linux systems.CVE-2024-6387: A signal handler race condition was found in sshd, where a

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).

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.)

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 issue exists because of an incomplete fix for CVE-2016-10009.

Last updated 22 September 2026

Last updated 22 September 2026

Last updated 22 September 2026

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.

In sshd and ssh in OpenSSH before 10.6, there is no check for whether the maximum packet length is exceeded during decompression of highly compressed data.

A flaw was found in OpenSSH sftp. During a copy, a server-supplied empty directory entry, a path made only of slashes, or a ".." basename is used as the local destination. The write runs as the user who started sftp, and the server must be one that user chose to copy from. This is an incomplete fix for CVE-2026-59995. That fix only stopped interactiveloop from building a command string. It does not rewrite these destination names. Reserve a new CVE. Do not reuse CVE-2026-59995.

OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kexalgorithms handling. This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in the default configuration, to jump to any location in the sshd address space. One third-party report states "remote code execution is theoretically possible."

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 successful attack can compromise the confidentiality of forwarded X11 traffic, including sensitive window contents and input, and may allow some manipulation of the forwarded session.

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.

Last updated 13 July 2026

Last updated 22 September 2026

A flaw was found in OpenSSH ssh. sshvalidruser did not reject '$' or a backslash that is not at the end of a username entered on the command line. Those characters still expand through %u in ProxyCommand or Match exec. Usernames written in the configuration file are not subject to this check. CVE-2026-35386 is already backported and rejects a different set of shell metacharacters, plus a trailing backslash. Hostnames in that fix already reject '$' and '\'. Usernames do not. This is a new CVE on top of CVE-2026-35386.

On affected platforms, if SSH session multiplexing was configured on the client side, SSH sessions (e.g, scp, sftp) multiplexed onto the same channel could perform file-system operations after a configured session timeout expired

A flaw was found in OpenSSH. Outbound compression used deflateInit with the default level, so every channel on a connection shared one LZ77 search buffer. A peer who can write on one channel can recover plaintext from another channel by observing ciphertext lengths, as described in "Crossing the Streams" (Fabian Bäumer and Marcus Brinkmann, 2026). The fix switches outbound compression to ZHUFFMANONLY, which removes LZ77 matching and lowers the compression ratio. The RHEL maintainer will take that fix. The OpenSSH client does not offer compression by default. The server zlib default is delayed compression, which applies only if the client offers it.

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.

A flaw was found in OpenSSH sshd when GSSAPIAuthentication is enabled. A partial GSSAPI exchange left gssapiclient, including an exported name and credential, for a later authentication attempt on the same connection. sshgssapistorecreds stored delegated credentials even when sshgssapiuserok had not succeeded. The RHEL maintainer confirmed that this does not authorize a later login. The impact is storage of a delegated credential that userok did not accept. RHEL ships GSSAPIAuthentication yes. On RHEL 10, GSSAPIDelegateCredentials defaults to yes, and storecreds returns early only when that switch is off. This is not CVE-2026-60000 (MaxAuthTries and GSSAPI) and not CVE-2026-3497 (GSSAPI key exchange).

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

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

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