CVE-2026-39831

—

CVSS 3.1

9.1 critical

EPSS

<1%p35

Published

May 22, 2026 (May 22, 2026)

Modified

Jul 23, 2026

Description

The Verify() method for FIDO/U2F security key types ([email protected], [email protected]) 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.

Vendors: golang
Products: crypto
Weakness: CWE-862
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

NVD CVE.org GitHub PoCs EPSS (0.4%)

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