CVE-2026-85590: Thorsten Phpmyfaq

High severity, CVSS 7.1. EPSS: 0.5% chance of exploitation in the next 30 days.

phpMyFAQ before 4.1.8 contains an authentication bypass vulnerability in its two-factor authentication (TOTP) disable functionality. The removeTwofactorConfig() handler (reachable via POST /api/user/remove-twofactor) verifies only that the user is logged in and that a valid CSRF token is supplied, then disables TOTP without requiring password re-entry or a current TOTP code. The same downgrade is also reachable inline via PUT /api/user/data/update, which accepts a plain twofactor_enabled form field under the same session+CSRF-only guard. An attacker who has hijacked a user's session can silently strip two-factor protection from any account, including administrator accounts, after which password-only authentication succeeds.

Affected products

• Thorsten Phpmyfaq: before 4.1.8 (fixed in 4.1.8)

Published 2026-09-04. Last modified 2026-09-08.