CVE-2026-46705
russh server userauth state is not reset when authentication principal changes
Description
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.
How to fix CVE-2026-46705
To remediate CVE-2026-46705, upgrade the affected package to a fixed version below.
- —upgrade to 0.61.0 or later
- —no fix listed
Is CVE-2026-46705 being exploited?
No exploitation signal available. Neither CISA KEV nor a current EPSS score has been published for CVE-2026-46705.
Affected packages (2)
- >= 0.34.0-beta.1, < 0.61.0
- from 0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |