CVE-2026-39831

Name	CVE-2026-39831
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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1137516

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
golang-go.crypto (PTS)	bullseye	1:0.0~git20201221.eec23a3-1	vulnerable
	bookworm	1:0.4.0-1	vulnerable
	trixie	1:0.25.0-1	vulnerable
	forky, sid	1:0.52.0-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
golang-go.crypto	source	(unstable)	1:0.52.0-1			1137516

Notes

[bullseye] - golang-go.crypto <postponed> (Limited support, follow bookworm DSAs/point-releases)
https://www.openwall.com/lists/oss-security/2026/05/22/6
https://github.com/golang/go/issues/79566