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

> Attackers can bypass CAPTCHA protections in AVideo by forcing short codes and brute-forcing them, enabling abuse of registration and recovery forms.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Apr 2026
- **Updated:** 22 Apr 2026
- **Also known as:** GHSA-hg7g-56h5-5pqr

## What is CVE-2026-40935?

CVE-2026-40935 is a medium-severity vulnerability in Wwbn Avideo, published on 21 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### 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.

Weakness: CWE-804 (Guessable CAPTCHA)

## Which versions are affected by CVE-2026-40935?

2 open source packages ship an affected version, including wwbn/avideo. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `wwbn/avideo` | Packagist | All versions to 29.0 | None |
| `wwbn/avideo` | Packagist | All versions to 29.0 | None |

Products: Wwbn Avideo.

## How do I fix CVE-2026-40935?

No fix has been published for CVE-2026-40935 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-40935 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40935 exists.

## Other vulnerabilities in Wwbn Avideo

- [CVE-2026-40911](https://insights.sbomify.com/CVE-2026-40911/): WWBN AVideo YPTSocket WebSocket Broadcast Relay Leads to Unauthenticated Cross-User JavaScript Execution via Client-Side eval() Sinks (critical 10.0)
- [CVE-2026-33478](https://insights.sbomify.com/CVE-2026-33478/): AVideo Multi-Chain Attack: Unauthenticated Remote Code Execution via Clone Key Disclosure, Database Dump, and Command Injection (critical 10.0)
- [CVE-2022-30534](https://insights.sbomify.com/CVE-2022-30534/): Command injection in AVideo (critical 9.9)
- [CVE-2022-30547](https://insights.sbomify.com/CVE-2022-30547/): Path traversal in AVideo (critical 9.9)
- [CVE-2022-32572](https://insights.sbomify.com/CVE-2022-32572/): Command injection in AVideo (critical 9.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40935 and fix it if it is affected.

What it is: CVE-2026-40935 is a medium-severity vulnerability in Wwbn Avideo, published on 21 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40935 exists.

Affected packages and fixed versions:
- wwbn/avideo (Packagist): affected all versions up to 29.0; no fix listed
- wwbn/avideo (Packagist): affected all versions up to 29.0; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-40935/ (Markdown: https://insights.sbomify.com/CVE-2026-40935/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40935
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40935
- OSV: https://osv.dev/vulnerability/CVE-2026-40935

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40935/
Summaries are generated and may contain mistakes; the official description above is the record.