# CVE-2026-128088: russh try_sign: asynchronous confirmation can sign after agent lock

Status: published. Published: 2026-11-13. Updated: 2026-11-13.

russh is a Rust SSH client and server library that includes an SSH agent protocol implementation. Prior to version 0.65.1, try_sign() captures an Arc<PrivateKey> before awaiting Agent::confirm() and does not revalidate the shared lock state or key presence after the await. This is a distinct residual defect in the remediation for CVE-2026-116794. A peer, including a remote SSH server using agent forwarding, can begin a confirmation-constrained signature request while the agent is unlocked and receive the signature after another connection locks the agent if the stale confirmation returns true. New post-lock requests are rejected and private key material is not disclosed, but the pending operation bypasses the current lock state. This issue is fixed in version 0.65.1.

## Remediation

- fix: russh (crates.io): OSV reports a fixed version 0.65.1. Check the advisory for supported release branches. (source: OSV GHSA-736f-c93q-9fwx) — https://github.com/advisories/GHSA-736f-c93q-9fwx

## Affected products and versions

- Eugeny / russh: >= 0.65.0, < 0.65.1 (affected). Source: CNA: GitHub_M
-  / russh (russh): 0.65.0 (affected, crates.io); ≥ 0.65.0; < 0.65.1 (affected, semver); OSV events: introduced 0.65.0; fixed 0.65.1. Source: OSV GHSA-736f-c93q-9fwx

## Severity and prioritization

- CVSS 3.1: 2.2 (low); CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-367, CWE-863

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/Eugeny/russh/security/advisories/GHSA-736f-c93q-9fwx (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/Eugeny/russh/pull/808 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/Eugeny/russh/commit/43a46d67a80a7355fcd2fb25e7e00d79aec8184c (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/Eugeny/russh/releases/tag/v0.65.1 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/advisories/GHSA-736f-c93q-9fwx (OSV / GitHub Security Advisories; advisory)

- https://osv.dev/vulnerability/GHSA-736f-c93q-9fwx (OSV / GitHub Security Advisories; osv)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-128088; retrieved 2026-11-13; source updated 2026-11-13

- OSV / GitHub Security Advisories: https://osv.dev/vulnerability/GHSA-736f-c93q-9fwx; retrieved 2026-11-13; source updated 2026-11-13

Revision: 3e5f5ffa788c988d4369d26c70232cf7ca6e80aac557dedea7ea0acd526eb159

Canonical: https://y2.dev/cve/CVE-2026-128088

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