CVE-2016-6474: A vulnerability in the implementation of X.509 Version 3 for SSH authentication functionality in Cisco IOS...

Security readout for executives and security teams

Cisco IOS and IOS XE devices may let a remote unauthenticated attacker bypass SSH authentication when X.509 Version 3 authentication is involved. For executives, this is a serious management-plane risk because affected routers or switches could be accessed without valid credentials if the vulnerable function is exposed. Exposure is most likely on Cisco IOS or IOS XE systems running affected software with SSH management reachable and X.509 Version 3 SSH authentication enabled or supported. The source bundle does not enumerate all affected platforms or configurations. Treat as high priority for network infrastructure with reachable SSH management. The issue is old, but legacy IOS and IOS XE deployments can persist for years. Prioritize upgrade or exposure reduction where management access crosses trust boundaries. Mitigation focus: Upgrade affected IOS or IOS XE systems to a Cisco-listed fixed release.; Review Cisco advisory guidance for CSCuv89417 before selecting target software.; Restrict SSH management access to trusted administration networks until upgraded..

Prepared

Jun 13, 2026, 13:16 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.