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.
History

Fri, 22 May 2026 04:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-296

Fri, 22 May 2026 03:30:00 +0000

Type Values Removed Values Added
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.
Title Invoking bypass of FIDO/U2F security keys physical interaction in golang.org/x/crypto/ssh
References

cve-icon MITRE

Status: PUBLISHED

Assigner: Go

Published:

Updated: 2026-05-22T02:31:27.436Z

Reserved: 2026-04-07T18:13:03.528Z

Link: CVE-2026-39831

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-22T04:16:22.553

Modified: 2026-05-22T04:16:22.553

Link: CVE-2026-39831

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-22T04:30:25Z