phpMyFAQ is an open source FAQ web application. Versions 4.0-nightly-2025-10-03 and below do not enforce uniqueness of email addresses during user registration. This allows multiple distinct accounts to be created with the same email. Because email is often used as an identifier for password resets, notifications, and administrative actions, this flaw can cause account ambiguity and, in certain configurations, may lead to privilege escalation or account takeover. This issue is fixed in version 4.0.13.