CVE-2026-119561: phpMyAdmin through 5.2.3 WebAuthn Two-Factor Authentication Bypass via CustomServer

phpMyAdmin through 5.2.3 contains an authentication bypass vulnerability in CustomServer::parseAndValidateAssertionResponse() that never verifies WebAuthn assertion signatures against stored public keys. Attackers holding a victim's MySQL credentials can POST a crafted webauthnrequestresponse with matching challenge, origin, and rpIdHash to bypass the second factor and gain database privileges.