phpMyFAQ - Authentication Bypass via Empty API Token

phpMyFAQ before 4.1.3 contains an authentication bypass vulnerability in API v4.0 where the default empty api.apiClientToken allows unauthenticated users to create and modify FAQ entries. Attackers can send an empty x-pmf-token header to bypass token validation and inject malicious content via POST endpoints /api/v4.0/faq/create, /api/v4.0/category, and /api/v4.0/question.