CVE-2026-39832 Invoking agent constraints dropped when forwarding keys in golang.org/x/crypto/ssh/agent

What is CVE-2026-39832?

CVE-2026-39832 is a critical vulnerability in golang.org/x/crypto/ssh/agent, published on 22 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

When adding a key to a remote agent constraint extensions such as [email protected] 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.

Weakness: CWE-502, CWE-281

Which versions are affected by CVE-2026-39832?

3 open source packages ship an affected version, including golang.org/x/crypto. It affects 1 product.

Products include Golang Crypto.

How do I fix CVE-2026-39832?

Upgrade golang.org/x/crypto to 0.52.0 or later.

Is CVE-2026-39832 being exploited?

There is no known exploitation of CVE-2026-39832 in the wild and no public exploit code.

Other vulnerabilities in golang.org/x/crypto/ssh/agent

• CVE-2026-46595 Invoking VerifiedPublicKeyCallback permissions skip enforcement in golang.org/x/crypto/ssh Critical 10.0
• CVE-2026-39830 Invoking client can cause server deadlock on unexpected responses in golang.org/x/crypto/ssh Critical 9.1
• CVE-2026-39831 Invoking bypass of FIDO/U2F security keys physical interaction in golang.org/x/crypto/ssh Critical 9.1
• CVE-2026-39833 Invoking key constraints not enforced in golang.org/x/crypto/ssh/agent Critical 9.1
• CVE-2026-39834 Invoking infinite loop on large channel writes in golang.org/x/crypto/ssh Critical 9.1

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-87200, AZL-87263, AZL-87275, AZL-87624, AZL-87717, AZL-88206 and 1113 more.