Medium severity · published Apr 21, 2026
CVE-2026-40935
WWBN/AVideo has CAPTCHA Bypass via Attacker-Controlled Length Parameter and Missing Token Invalidation on Failure
5.3
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 12% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AV
AVideo · WWBN
<= 29.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-40935
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-40935
Patch
https://github.com/WWBN/AVideo/commit/bf1c76989e6a9054be4f0eb009d68f0f2464b453
Exploit
https://github.com/WWBN/AVideo/security/advisories/GHSA-hg7g-56h5-5pqr
More from AVideo
10.0
CVE-2026-40911
WWBN AVideo YPTSocket WebSocket Broadcast Relay Leads to Unauthenticated Cross-User JavaScript Execution via Client-Side eval() Sinks
10.0
CVE-2026-33478
AVideo Multi-Chain Attack: Unauthenticated Remote Code Execution via Clone Key Disclosure, Database Dump, and Command Injection
9.9
CVE-2022-30547
A directory traversal vulnerability exists in the unzipDirectory functionality of WWBN AVideo 11.6 and dev master commit 3f7c0364
9.8
CVE-2026-86189
WWBN AVideo Unauthenticated Path Traversal via notify.ffmpeg.json.php
9.8
CVE-2026-85154
WWBN AVideo Authentication Bypass via Non-Expiring video_id_hash
