CVE-2026-40935
WWBN/AVideo has CAPTCHA Bypass via Attacker-Controlled Length Parameter and Missing Token Invalidation on Failure
WWBN AVideo is an open source video platform. In versions 29.0 and prior, `objects/getCaptcha.php` accepts the CAPTCHA length (`ql`) directly from the query string with no clamping or sanitization, letting any unauthenticated client force the server to generate a 1-character CAPTCHA word. Combined with a case-insensitive `strcasecmp` comparison over a ~33-character alphabet and the fact that failed validations do NOT consume the stored session token, an attacker can trivially brute-force the CAPTCHA on any endpoint that relies on `Captcha::validation()` (user registration, password recovery, contact form, etc.) in at most ~33 requests per session. Commit bf1c76989e6a9054be4f0eb009d68f0f2464b453 contains a fix.
- Affected
- WWBN · AVideo
- CVSS v3.1 GITHUB
- 5.3 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - EPSS
- 0.32% chance of exploitation in the next 30 days, 23rd percentile
- Published
- 2026-04-21
- Updated
- 2026-04-22
Proof-of-concept exploits (1)
Security advisories
- WWBN/AVideo/security/advisories/GHSA-hg7g-56h5-5pqr
- WWBN/AVideo/commit/bf1c76989e6a9054be4f0eb009d68f0f2464b453