CVE-2026-116794: russh: Missing user confirmation for keys in SSH agent server

Summary

russh, a Rust SSH client and server library, does not call the Agent::confirm method for keys added with the confirm constraint (ssh-add -c) in its agent server. Applications that override Agent::confirm to require user approval are affected. An attacker who can reach the agent socket, including the remote side of a forwarded agent, can use such a key to authenticate or sign data as the user without approval while the key remains loaded.

Affected

russh from 0.50.0-beta.12 up to, but not including, 0.65.0
Only applications that run the russh agent server and override Agent::confirm are affected.

Fixed in

Upgrade to russh 0.65.0 or later.

Workaround

If upgrading is not possible, implement the approval check in the Agent::confirm_request hook, which still runs for every signing request.
Do not forward agent sockets to untrusted hosts.
Remove keys loaded with ssh-add -c from russh-based agents if confirmation matters.

Exploitation

No evidence of exploitation in the wild found. Not listed in CISA KEV.
EPSS 0.16 % (percentile 5).
No public proof of concept found.

Our recommendation

Identify software in your environment that uses russh, for example developer tools, automation tools or SSH clients, and ask vendors whether they use it and which version.
Update affected software or in-house builds to russh 0.65.0 or later in the normal patch cycle, with higher priority for products that use a russh agent with approval prompts.
Check whether forwarded agent sockets are used on systems running affected software.

Public exploits

PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.

Research sources

GitHub security advisory GHSA-vp5q-ff62-jwqv github.com
russh v0.65.0 release github.com
Fix commit: call Agent::confirm github.com
Regression commit: Native async traits encore github.com
GitLab advisory CVE-2026-116794 advisories.gitlab.com
OSV GHSA-vp5q-ff62-jwqv osv.dev

Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 1 Nov 2026, 13:06.

Original description (NVD)

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.

NVD references (4)

Sources

The tracker combines official, freely usable data sources – updated continuously:

NVD (NIST) – CVEs, rating (CVSS), affected products
CISA KEV – vulnerabilities confirmed by CISA as actively exploited
CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
FIRST EPSS – probability of exploitation
Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
PoC-in-GitHub – public proof-of-concept repositories
Metasploit (Rapid7) – modules of the Metasploit Framework
Exploit-DB (OffSec) – archive of public exploits (links only)
Patch days: official vendor pages (linked per vendor) (Vendor patch days)

Affected? We can help.

We check whether your systems are affected, install updates and close the gap – continuously with the System Health Checker if you wish.

Get in touch RSS feed