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HighVulnerabilityCVE-2026-116794updated 30 Oct 2026, 22:59 UTC

russh SSH agent skips the user confirmation prompt for keys added with -c

Keys added to the SSH agent with the 'ask me first' option (ssh-add -c) can be used without asking the user. Anyone who can reach the agent socket, including a remote host you forwarded your agent to, may sign in as you.

Fixed in russh 0.65.0 · out Official, 2 sources
SeverityHighCVSS 8.3 of 10
Being exploited?UnclearNo reports either way yet
Fix available?Yesrussh 0.65.0 · since 30 Oct 2026
How sure is this?Official, 2 sourcesBacked by an official source

How the attack works simplified

  1. 1Process with socket accessLocal process or remote forwarded agent
  2. 2Requests a signatureUses a key added with ssh-add -c
  3. 3Agent skips confirmationtry_sign hard-codes approval
  4. 4Never promptedAgent::confirm is never called
  5. ResultAttacker signs or logs in as the user

What happened

In russh's agent server, Connection::try_sign replaces the Agent::confirm call with a hard-coded success for keys carrying SSH_AGENT_CONSTRAIN_CONFIRM, so user-approval hooks in Agent::confirm are bypassed.

Why it is dangerous: Applications that rely on Agent::confirm to require approval for signing lose that check, letting a process with socket access authenticate or sign as the user while the key stays loaded.

Are you affected?

You are affected if you use russh 0.50.0-beta.12 through 0.64.1 in an agent server and override Agent::confirm to require user approval or another policy check.

Package / productAffected versionsFixed in
russh · rust< 0.650.65

What to do

  1. Update russh to 0.65.0 or later
  2. If you cannot update yet, do not rely on Agent::confirm for approval; add the check in Agent::confirm_request, which still runs for every signing request
  3. Remove keys added with ssh-add -c from agents exposed to untrusted users or forwarded hosts until updated

Timeline

  1. 28 Oct 2026, 18:17 UTC
    Publicly disclosed
  2. 28 Oct 2026, 18:17 UTC
    Reported by NVD · NVD
  3. 28 Oct 2026, 18:17 UTC
    Picked up by Zero Radar
  4. 30 Oct 2026, 22:59 UTC
    GitHub Advisory reported on it · GitHub Advisory
  5. 30 Oct 2026, 22:59 UTC
    Fixed version published: russh 0.65 · GitHub Advisory

Sources 2 reports, oldest first

Official vendor, government CERT or advisory database

Technical details

ID
CVE-2026-116794 · GHSA-vp5q-ff62-jwqv
CVSS
8.3 / 10
EPSS
0.2% chance of exploitation within 30 days
Disclosed
28 Oct 2026, 18:17 UTC
On Zero Radar
28 Oct 2026, 18:17 UTC (1 min after disclosure)
Last change
30 Oct 2026, 22:59 UTC

The plain-language parts and the attack diagram were written by an AI model (anthropic/claude-haiku-5.5) from the sources above. Facts like versions, exploitation and dates come from the sources themselves. How Zero Radar works

russh SSH agent skips the user confirmation prompt for keys added with -c · Zero Radar