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Fencer Intel
low 2.2

CVE-2026-128088 json

russh try_sign: asynchronous confirmation can sign after agent lock

published yesterday modified yesterday also GHSA-736f-c93q-9fwx , EUVD-2026-125722

cvss
2.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits
0
none known

Summary

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.

Patch / fix

  • crates.io russh 0.65.1

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-128088 updated cvss 2.2

russh: russh: SSH agent lock bypass via unverified state during confirmation

  • Red Hat Hardened Images openshell 0.1.8-0.1.hum1
    affected: workaround, no fix available

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.11% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-14).

CVSS scores

assigned by version score vector
CNA 3.1 2.2 CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N
GitHub 3.1 2.2 CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
crates.io russh
>=0.65.0, <0.65.1
0.65.1

Affected products

  • Eugeny russh

Classification

Weakness
  • CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
  • CWE-863 Incorrect Authorization

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.