---
id: "CVE-2026-116794"
kind: "vulnerability"
aliases: ["CVE-2026-116794"]
title: "russh: SSH agent server skips per-key confirmation, letting unapproved signing"
severity: "high"
cvss: 8.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["package", "russh", "rust", "self-hosted", "ssh-agent"]
not_affected_if: ["default-confirm", "no-agent-server"]
published_at: "2026-10-28T18:17:14+00:00"
first_seen_at: "2026-10-28T18:34:33+00:00"
updated_at: "2026-10-28T18:34:50+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-116794", "first_seen_at": "2026-10-28T18:34:33+00:00"}]
---

# russh: SSH agent server skips per-key confirmation, letting unapproved signing

russh, a Rust SSH client and server library, has an SSH agent server that accepts keys added with the confirm constraint but never runs the application's confirm check. A process that can reach the agent socket, including a remote host using forwarded agent access, can sign with such a key without the approval the application meant to require.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the russh version in Cargo.lock: `grep -A1 'name = "russh"' Cargo.lock`
- Check whether the application implements a custom `Agent::confirm` in russh's agent server code

## Fix

- Upgrade russh to `0.65.0` or later
- Until upgraded, implement the approval logic in `Agent::confirm_request`, which still runs for every signing request

## Timeline

- 2026-10-28T18:34:33+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-116794

## From the sources

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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_