CVE-2026-46705
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedRussh 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe russh SSH library fails to properly isolate authentication state when the user or service name changes between SSH_MSG_USERAUTH_REQUEST messages. This internal state mismatch allows authentication-related data (remaining methods, partial-success state) from one principal's auth attempt to influence subsequent attempts for different users/services, potentially enabling authentication bypass or privilege escalation.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify russh as a dependencySearch your project dependencies (Cargo.toml, Cargo.lock) for the 'russh' crateAffected if russh is listed as a direct or transitive dependency
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Check installed russh versionExamine Cargo.lock or run 'cargo tree -p russh' to find the exact version numberAffected if The version is below 0.61.0 (e.g., 0.60.0, 0.59.x, etc.)
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Confirm server implementation usageSearch codebase for 'russh::server' module imports, 'Server' struct usage, or sshd configuration that uses russhAffected if Your application uses the russh server component rather than just the client
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Verify multi-user authentication pathInspect authentication logic for scenarios where different usernames or principals can be attempted on a single SSH connection sessionAffected if Your SSH server allows multiple authentication requests with different usernames on the same connection before successful authentication
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Check for authentication state persistenceReview whether your russh server implementation maintains authentication state across multiple SSH_MSG_USERAUTH_REQUEST messages within one connectionAffected if The server retains authentication method state, partial-success state, or in-progress method state between attempts
You are affected if your application uses russh as an SSH server with a version below 0.61.0 and permits multiple authentication attempts with changing usernames on the same connection.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpgrade russh to version 0.61.0 or later. Since this is a library vulnerability, any SSH server using the affected versions must update the library dependency.
0.61.0
- Locate the russh dependency in your project's Cargo.toml file
- Update the russh version constraint to specify version 0.61.0 or later (e.g., russh = "0.61.0")
- Run `cargo update` to fetch the updated dependency
- Run `cargo build` to compile with the fixed version
- Verify SSH authentication functionality works correctly in your application
- Rebuild and redeploy your application with the patched library
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-46705 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-46705 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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