Vulnerability Description
russh is a Rust SSH client and server library that includes an SSH agent protocol implementation. Prior to 0.65.0, the client Session::process_packet path in russh/src/client/encrypted.rs accepts repeated packets encoded with russh's private msg::EXT_INFO = 7 before authentication, while the standards-compliant EXT_INFO message number 82 does not reach the affected handler. The handle_ext_info function appends every parsed extension name to received_extensions without clearing, deduplicating, or bounding the vector. A malicious SSH server that deliberately sends private message number 7 can therefore retain an unbounded number of attacker-controlled extension names for the session lifetime, causing progressive client memory exhaustion. This issue is fixed in version 0.65.0.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/Eugeny/russh/commit/b33e93beec393e6d29eee69c1b8831736724ee75
- https://github.com/Eugeny/russh/releases/tag/v0.65.0
- https://github.com/Eugeny/russh/security/advisories/GHSA-4p9f-7p9m-5vfg
- https://github.com/Eugeny/russh/security/advisories/GHSA-4p9f-7p9m-5vfg
FAQ
What is CVE-2026-116773?
CVE-2026-116773 is a vulnerability with a CVSS score of 4.3 (MEDIUM). russh is a Rust SSH client and server library that includes an SSH agent protocol implementation. Prior to 0.65.0, the client Session::process_packet path in russh/src/client/encrypted.rs accepts repe...
How severe is CVE-2026-116773?
CVE-2026-116773 has been rated MEDIUM with a CVSS base score of 4.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-116773?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.