Vulnerability · Published Apr 21, 2026 · Assigned by GitHub_M

CVE-2026-40935WWBN/AVideo has CAPTCHA Bypass via Attacker-Controlled Length Parameter and Missing Token Invalidation on Failure

Medium 5.3

In plain English

A medium-severity security flaw in AVideo from WWBN. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 12% of all known vulnerabilities).

Severity (CVSS 3.1)5.3Medium

Exploit odds (30 days)0.2%top 87.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	wwbn/avideo	no fix listed	GHSA-hg7g-56h5-5pqr

Affected products (as reported)

Vendor	Product	Versions
WWBN	AVideo	<= 29.0

Weakness: CWE-804 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

References

https://github.com/WWBN/AVideo/security/advisories/GHSA-hg7g-56h5-5pqr x_refsource_CONFIRM
https://github.com/WWBN/AVideo/commit/bf1c76989e6a9054be4f0eb009d68f0f2464b453 x_refsource_MISC