Auth bypass in Phpmyfaq
CVE-2026-27836
phpMyFAQ is an open source FAQ web application. Prior to version 4.0.18, the WebAuthn prepare endpoint (`/api/webauthn/prepare`) creates new active user accounts without any authentication, CSRF protection, captcha, or configuration checks. This allows unauthenticated attackers to create unlimited user accounts even when registration is disabled. Version 4.0.18 fixes the issue.
Vulnerability class: Broken Access Control
EPSS: 0.004 (34.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
Affected products
- Phpmyfaq
- Thorsten Phpmyfaq — versions < 4.0.18
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-27836?
- CVE-2026-27836 is a high-severity vulnerability in Phpmyfaq, classified under Missing Authorization. CVSS score: 7.5/10. Published 2026-02-27.
- How severe is CVE-2026-27836?
- High severity. CVSS v3 base score is 7.5 out of 10.