VulnerabilityModified

CVE-2026-39832

When adding a key to a remote agent constraint extensions such as restrict-destination-v00@openssh.com were not serialized in the request.

CRITICAL 9.1EPSS 0.60%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.60%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

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: 9.1 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS: 0.60% probability · 47th percentile
CISA KEV: Not listed
Weakness: CWE-502, CWE-281
Affected: golang/crypto
Source: security@golang.org

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.