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TI-2026-82122 Aliases CVE-2026-116794GHSA-vp5q-ff62-jwqv

Missing confirmation check in russh SSH agent for constrained keys

Priority HIGH 69CWE-862Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
None · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-862.

Summary

The agent server in russh, a Rust SSH client and server library, returns success for keys added with the confirm constraint without calling the Agent::confirm hook, in versions from 0.50.0-beta.12 before 0.65.0. The missing authorization check (CWE-862) lets signing skip the user approval that an application's confirm policy requires. A local process that can reach the agent socket, or the remote side of a forwarded agent, can sign data as the user while the key stays loaded, if the application overrides Agent::confirm.

Written with Claude Haiku 5.5 from the sources below · 2026-11-03

Description from the CNA

russh is a Rust SSH client and server library that includes an SSH agent protocol implementation. From 0.50.0-beta.12 until 0.65.0, the agent server's Connection::try_sign path in russh/src/keys/agent/server.rs recognizes SSH_AGENT_CONSTRAIN_CONFIRM but returns a hard-coded successful result instead of calling Agent::confirm. In applications that override Agent::confirm to require user approval or another policy check, a process that can reach the agent socket, including the remote side of a forwarded agent, can use a key added through ssh-add -c without that check and can authenticate or sign data as the user while the key remains loaded. The separate Agent::confirm_request hook still runs for every signing request, so checks implemented there remain effective, and implementations that retain the default always-successful Agent::confirm do not lose an approval check through this regression. This issue is fixed in version 0.65.0.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00156 4th percentileScored 2026-11-07
Fix Fixed russh (Eugeny): 0.65russh (crates.io): 0.65Red Hat: 1 advisory

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Eugenyrusshbefore 0.650.65Patch availableCNA
—russh (crates.io)before 0.650.65Patch availableGHSA-vp5q-ff62-jwqv
  • russh VendorEugeny Affected before 0.65 Fixed in 0.65 Patch available CNA
  • russh (crates.io) Vendor— Affected before 0.65 Fixed in 0.65 Patch available GHSA-vp5q-ff62-jwqv

Remediation

Upgrade russh to version 0.65.0. Red Hat Hardened Images is fixed in RHSA-2026:93904, released 2026-11-02.

Written with Claude Haiku 5.5 from the sources below · 2026-11-03

  • Fix · CNA russh (Eugeny) Fixed in 0.65
  • Fix · GHSA-vp5q-ff62-jwqv russh (crates.io) Fixed in 0.65 Advisory →

Red Hat 1 advisory

  • RHSA-2026:93904 Released 2026-11-02 · Red Hat rating Moderate
    Red Hat Hardened Images RPMs Security Update
    • Red Hat Hardened Images openshell-0.1.6-0.1.hum1@aarch64, openshell-0.1.6-0.1.hum1@src, openshell-0.1.6-0.1.hum1@x86_64 +4

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Hardened ImagesFixed RHSA-2026:93904

Timeline

  1. 2026-10-28 Threatist record created from CVE-2026-116794
  2. 2026-10-30 Priority changed: MEDIUM → LOW
  3. 2026-10-30 Affected versions changed · Red Hat
  4. 2026-10-30 CVSS score added · Red Hat
  5. 2026-10-30 Alias added: GHSA-vp5q-ff62-jwqv
  6. 2026-10-30 Fix available: crates.io/[email protected] · GHSA-vp5q-ff62-jwqv
  7. 2026-10-30 CVSS score added · GHSA-vp5q-ff62-jwqv
  8. 2026-10-30 Weakness changed · GHSA-vp5q-ff62-jwqv
  9. 2026-10-30 6 new references · GHSA-vp5q-ff62-jwqv
  10. 2026-10-31 CVSS score changed · Red Hat
  11. 2026-11-03 Fix available: RHSA-2026:93904 · Red Hat
  12. 2026-11-03 Fix available: Red Hat Hardened Images · Red Hat
  13. 2026-11-03 CISA SSVC decision points changed
  14. 2026-11-03 Priority changed: LOW → HIGH

References

Advisory 1

Other 5

  • TI-2026-65512 russh: Client-side channel-scoped Handler callbacks fire for channel IDs the client never opened CVSS 3.1HIGH 7.5
  • TI-2026-35550 Russh: SSH message fields were decoded through allocation-first parsers before field-specific bounds CVSS 3.1HIGH 7.5
  • TI-2026-34331 Russh: Post-decompression SSH packet size was not bounded, allowing remote oversized compressed packets CVSS 3.1HIGH 7.5
  • TI-2026-34308 Resource allocation without limits in Eugeny russh CVSS 3.1HIGH 7.5
  • TI-2025-16084 Tabby has a TCC Bypass via Misconfigured Node Fuses CVSS 4.0HIGH 8.6
  • TI-2024-36991 Tabby has a TCC Bypass via Unnecessary Permissive Entitlements in Tabby CVSS 4.0HIGH 8.6
See all 25 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences