CVE-2026-46705: medium-severity vulnerability in Eugeny russh
russh server userauth state is not reset when authentication principal changes
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.3epss 0.2%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Affected products
Eugeny · russhRelated CVEs — Eugeny russh
In the same product, most dangerous first.
CVE-2024-43410HIGHRussh has an OOM Denial of Service due to allocation of untrusted amountEPSS 0.9%CVE-2026-73430MEDIUMRussh: Pre-auth remote panic via all-zero Curve25519 peer public value (encode_mpint OOB)EPSS 0.6%CVE-2026-73429MEDIUMRussh: client wrong-length X25519 `clone_from_slice` panic (pre-auth DoS)EPSS 0.5%CVE-2026-42189HIGHRussh: Pre-auth DoS via unbounded allocation in keyboard-interactive authEPSS 0.5%CVE-2026-73489MEDIUMRussh: Post-auth remote panic via pty-req with more than 130 terminal-mode recordsEPSS 0.5%CVE-2025-54804MEDIUMRussh is missing an overflow check during channel windows adjustEPSS 0.4%