russh server userauth state is not reset when authentication principal changes

Summary The russh server authentication path keeps internal userauth state across SSHMSGUSERAUTHREQUEST messages without separating that state when the request principal changes. RFC 4252 allows the user name and service name fields to change between authentication requests. The issue is not that...

PT-2026-45018

Name of the Vulnerable Software and Affected Versions Russh versions 0.34.0-beta.1 through 0.60.x Description The server authentication path in the Russh library fails to separate internal user authentication state when the request principal changes across SSH MSG USERAUTH REQUEST messages...