Threats affecting pkg:github/nextcloud/twofactor_webauthn

CVE-2025-66558 is a low-severity authorization bypass vulnerability in Nextcloud's Twofactor WebAuthn provider affecting versions prior to 1.4.2 and 2.4.1. The flaw arises from a missing ownership check that allows an attacker to take control of a victim's 2FA WebAuthn device by guessing a long random key string (80-128 characters). Although the attacker cannot authenticate as the victim, they can force the victim to re-register a new 2FA device upon next login, potentially disrupting user experience and 2FA integrity. The vulnerability requires remote network access, low privileges, and high attack complexity, with no user interaction needed. No known exploits are reported in the wild, and patches are available in versions 1.4.