CVE-2026-40935

WWBN/AVideo has CAPTCHA Bypass via Attacker-Controlled Length Parameter and Missing Token Invalidation on Failure

State
Published
Severity
5.3 Medium
Published
Apr 21, 2026
Updated
Apr 22, 2026
Reserved
Apr 15, 2026

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Description

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.

Scores

CVSSScoreVectorSource
3.15.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:NGitHub_M

Weaknesses

Affected Products

ProductVersions
AVideoWWBN
  • <= 29.0Affected

References

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