CVE-2026-39832criticalCWE-281

CVE-2026-39832: critical vulnerability in golang.org/x/crypto/ssh/agent

Invoking agent constraints dropped when forwarding keys in golang.org/x/crypto/ssh/agent

Published 22 May 2026 · Updated 15 Sep 2026

28Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 9.1epss 0.7%

exploitation probability

0.7%top 48% of all CVEs

observed exploitation

nono source reports it

When adding a key to a remote agent constraint extensions such as restrict-destination-v00@openssh.com were not serialized in the request. Destination restrictions were silently stripped when forwarding keys, allowing unrestricted use of the key on the remote host. The client now serializes all constraint extensions. Additionally, the in-memory keyring returned by NewKeyring() now rejects keys with unsupported constraint extensions instead of silently ignoring them.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

golang.org/x/crypto · golang.org/x/crypto/ssh/agent

Related CVEs — golang.org/x/crypto/ssh/agent

In the same product, most dangerous first.

CVE-2025-47913HIGHPotential denial of service in golang.org/x/crypto/ssh/agentEPSS 0.7%CVE-2025-47914MEDIUMMalformed constraint may cause denial of service in golang.org/x/crypto/ssh/agentEPSS 0.5%CVE-2026-39833CRITICALInvoking key constraints not enforced in golang.org/x/crypto/ssh/agentEPSS 0.5%CVE-2026-46598MEDIUMInvoking pathological inputs can lead to client panic in golang.org/x/crypto/ssh/agentEPSS 0.4%

References