CVE-2026-39831
Critical · CVSS 9.1- CVSS
- 9.1
- nvd
- EPSS
- 0.37%
- 30th pct
- KEV
- No
- Class
- oss containerizable
- CWE-862
Description
The Verify() method for FIDO/U2F security key types (sk-ecdsa-sha2-nistp256@openssh.com, sk-ssh-ed25519@openssh.com) did not check the User Presence flag. Signatures generated without physical touch were accepted, allowing unattended use of a hardware security key. To restore the previous behavior, return a "no-touch-required" extension in Permissions.Extensions from PublicKeyCallback.
Affected packages
| Go | golang.org/x/crypto | 0 → 0.52.0 |
References
Status: profiled · ingested 2026-07-23T18:00:18.000Z