OpenSSH Security Flaws

Privilege-escalation exposure in OpenSSH before 10.3 (fixed in 10.3p1) where scp, when run by root using the legacy SCP protocol flag -O and without -p (preserve mode), may write a downloaded file with setuid or setgid bits set, contrary to user expectation. A malicious or compromised SSH server (or a man-in-the-middle on the transfer) could thereby cause an attacker-controlled binary to land on disk as a setuid/setgid-root executable, enabling local privilege escalation when it is later run. There is no public exploit identified at time of analysis, EPSS is very low (0.04%), and CISA SSVC rates exploitation as 'none' though technical impact as 'total'.

Argument/command injection in OpenSSH before 10.3 lets shell metacharacters embedded in an untrusted username trigger command execution on the SSH-client host. It affects deployments that both feed an attacker-influenced username to the ssh command line and use a non-default ssh_config where %-token expansion (e.g. in ProxyCommand/LocalCommand) is enabled. There is no public exploit identified at time of analysis, EPSS is negligible (0.01%), and it is not in CISA KEV; a fixed release (10.3/10.3p1) is available.

OpenSSH before 10.3 incorrectly interprets ECDSA algorithm specifications in PubkeyAcceptedAlgorithms and HostbasedAcceptedAlgorithms configuration options, allowing authenticated users to authenticate using unintended ECDSA variants. The vulnerability requires authenticated network access and high attack complexity, resulting in a low CVSS score of 3.1 with integrity impact but no confidentiality or availability loss. No public exploit code or active exploitation has been documented.

OpenSSH before 10.3 fails to confirm connection multiplexing in proxy-mode sessions, allowing local attackers with user interaction to bypass intended access controls and potentially manipulate multiplexed connections. The vulnerability affects OpenSSH versions prior to 10.3p1 and requires local access with user interaction (UI:R) on the affected system; while the CVSS score is low (2.5) and integrity impact is limited, the omission of confirmation mechanisms in proxy-mode multiplexing creates a logic flaw that could enable unauthorized session hijacking or redirection in multi-user environments.