Executive brief
phpMyFAQ is an open-source knowledge base system used by organizations to manage and share frequently asked questions. A security flaw in its programming interface (API) allows unauthorized individuals to bypass security checks and modify the knowledge base. An attacker could use this to create fake FAQ entries, delete categories, or inject malicious links and phishing content into the public-facing site, potentially damaging the organization's reputation or misleading its users.
Technical details
An authentication bypass exists in phpMyFAQ's REST API v4.0 due to insecure default initialization of the 'api.apiClientToken' configuration. During installation, this token is seeded as an empty string. The 'hasValidToken()' method in 'AbstractController.php' performs a strict inequality check between the configured token and the 'x-pmf-token' HTTP header provided by the client. Because both values default to an empty string, an attacker can bypass authentication by simply providing an empty 'x-pmf-token' header. This allows unauthorized POST and PUT requests to endpoints such as '/api/v4.0/faq/create', '/api/v4.0/category', and '/api/v4.0/question'. The issue is resolved in version 4.1.3.
Affected products
- thorsten phpMyFAQ < 4.1.3
Timeline
- 2026-05-14: advisory: Vendor security advisory published on GitHub
- 2026-05-28: disclosed: CVE published to NVD and VulnCheck advisory released