CVE-2026-46705 Details
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.
A vulnerability exists in the russh library, which is a Rust SSH client and server library, in versions 0.34.0-beta.1 prior to 0.61.0. The issue arises because the russh server's authentication process retains internal user authentication state across SSH_MSG_USERAUTH_REQUEST messages without properly separating that state when the request principal changes. According to RFC 4252, the user name and service name can vary between authentication requests. While such changes are permissible, the russh library fails to reset its authentication state, which includes remaining methods, partial-success indicators, and in-progress method states, before processing a new request for a different user or service. This oversight can lead to an internal state mismatch, where authentication decisions for one user inadvertently affect another.
Users should update to russh version 0.61.0 or later, where this vulnerability has been patched.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Jun 10, 2026CISA-ADP
Assessed Jun 11, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/Eugeny/russh/security/advisories/GHSA-hpv4-5h6f-wqr3 | CISA-ADP | AdvisoryExploitRemedyVendor |
| https://github.com/Eugeny/russh/security/advisories/GHSA-hpv4-5h6f-wqr3 | [email protected] | AdvisoryExploitRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-287 | Improper Authentication | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Eugeny russh | >= 0.34.0-beta.1, < 0.61.0 (semver) |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 23, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 11, 2026 | CVE Modified | CISA-ADP |
| Jun 10, 2026 | New CVE Received | [email protected] |