GO-2026-5019

vendorUSosv

Invoking bypass of FIDO/U2F security keys physical interaction in golang.org/x/crypto/ssh

view advisory published 2026-05-22Licence: per source

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.

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describes (1)

Related CVEs.

IDseverity exploitable
CVE-2026-39831US—OT elevated—
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 with…
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