NVD Vulnerability Detail
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CVE-2026-39831
Summary

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.

Publication Date May 22, 2026, 1:16 p.m.
Registration Date May 23, 2026, 4:08 a.m.
Last Update May 22, 2026, 1:16 p.m.
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