CVE-2026-39832

A flaw was found in golang.org/x/crypto/ssh/agent. When a key was added to a remote agent, security restrictions, known as constraint extensions, were not properly processed during the request. This allowed these restrictions to be silently removed when keys were forwarded, leading to the unrestricted use of the key on the remote host. This vulnerability could enable an attacker to bypass intended security controls and perform unauthorized actions.

This Important vulnerability in golang.org/x/crypto/ssh/agent allows for a security bypass when SSH keys with destination restrictions are forwarded via an SSH agent. This flaw could lead to unintended exposure of SSH keys, enabling an attacker to use the forwarded key without the specified restrictions on remote hosts. Red Hat products utilizing golang.org/x/crypto/ssh/agent for key forwarding may be affected if users rely on constraint extensions for limiting key usage.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.