CVE-2026-46705: 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 ...

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.

Metrics

CVSS 3.1

5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS Probability

0.22%

12.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-287

References

Timeline

Published: Jun 10, 2026
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2026-46705?

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 severe is CVE-2026-46705?

CVE-2026-46705 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.22% probability of exploitation in the next 30 days.

How do I fix CVE-2026-46705?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.