russh: Asynchronous confirmation bypasses agent lock

A race condition in russh 0.65.0 allows a sign request to complete after an agent is locked by retaining a reference to the private key across an async confirmation await. An agent-forwarding peer can obtain a signature while the agent should be locked and rejecting requests.

Disclosed 13 November 2026 · Record updated 13 November 2026

Impact

A sign request can bypass agent lock protection by snapshots the private key before confirmation and retaining it while the agent transitions to locked state

Our coverage

A locked vault door swings open just as a second hand reaches through, completing a signature stamp before security mechanisms fully engage.

Vulnerabilities

Race condition lets russh SSH agent sign after being locked

An advisory published on 13 November 2026 says russh 0.65.0 can complete a signature request after another connection locks the agent.

13 Nov 2026

Sources

github.comhttps://github.com/advisories/GHSA-736f-c93q-9fwx