CVE-2026-46705

CVE-2026-46705 is a medium-severity vulnerability with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

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.

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 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2026-46705 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-46705?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-46705 have an EU (EUVD) identifier?
Yes. CVE-2026-46705 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-36126.
When was CVE-2026-46705 published?
CVE-2026-46705 was published on 2026-06-10 and last updated on 2026-06-17.

References

Other CWE-287 (Improper Authentication) vulnerabilities

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