CVE-2026-39831
Our Analysis: Environment Specific
Our model has classified this vulnerability as relevant to Environment Specific Systems, helping your team prioritize efforts effectively.
Published Date
May 22, 2026
Last Modified
May 22, 2026
CVSS Vector
Not Available
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.