CVE-2026-46705
MediumCVSS 5.3Exploitation Probability (EPSS)
Low risk11th percentile — higher than 11% of all known CVEs
Summary
Russh is a Rust SSH client & server library. From version 0.34.0-beta.1 to before version 0.61.0, the user authentication state is kept internally, which may lead to incorrect processing of authentication requests when the user or service changes.
Risk Assessment
Organizations may be exposed to unauthorized access as the authentication state can influence later requests for different users or services. This could lead to serious security vulnerabilities.
Recommendation
It is recommended to update the russh library to version 0.61.0 or later to mitigate this vulnerability.
Original NVD description (English source)
Russh is a Rust SSH client & server library. From version 0.34.0-beta.1 to before version 0.61.0, the russh server authentication path keeps internal userauth state across SSH_MSG_USERAUTH_REQUEST 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 such changes are invalid. The issue is that russh-owned authentication state, such as remaining methods, partial-success state, and in-progress method state, can remain associated with the connection and then influence a later request for a different (user, service). This is an internal library state mismatch. This issue has been patched in version 0.61.0.