# CVE-2026-40911: WWBN AVideo YPTSocket WebSocket Broadcast Relay Leads to Unauthenticated Cross-User JavaScript Execution via Client-Side eval() Sinks

> Unauthenticated attackers can execute arbitrary JavaScript in all connected users' browsers via unsanitized WebSocket messages, leading to account takeover.

- **Severity:** Critical 10.0 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`)
- **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-gph2-j4c9-vhhr

## What is CVE-2026-40911?

CVE-2026-40911 is a critical cross-site scripting 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, the YPTSocket plugin's WebSocket server relays attacker-supplied JSON message bodies to every connected client without sanitizing the `msg` or `callback` fields. On the client side, `plugin/YPTSocket/script.js` contains two `eval()` sinks fed directly by those relayed fields (`json.msg.autoEvalCodeOnHTML` at line 568 and `json.callback` at line 95). Because tokens are minted for anonymous visitors and never revalidated beyond decryption, an unauthenticated attacker can broadcast arbitrary JavaScript that executes in the origin of every currently-connected user (including administrators), resulting in universal account takeover, session theft, and privileged action execution. Commit c08694bf6264eb4decceb78c711baee2609b4efd contains a fix.

Weakness: CWE-94 (Improper Control of Generation of Code)

## Which versions are affected by CVE-2026-40911?

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-2026-40911?

No fix has been published for CVE-2026-40911 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-40911 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40911 exists.

## Other vulnerabilities in Wwbn Avideo

- [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)
- [CVE-2026-33352](https://insights.sbomify.com/CVE-2026-33352/): AVideo has an Unauthenticated SQL Injection via `doNotShowCats` Parameter (Backslash Escape Bypass) (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40911 and fix it if it is affected.

What it is: CVE-2026-40911 is a critical cross-site scripting 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-2026-40911 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-2026-40911/ (Markdown: https://insights.sbomify.com/CVE-2026-40911/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40911
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40911
- OSV: https://osv.dev/vulnerability/CVE-2026-40911

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40911/
Summaries are generated and may contain mistakes; the official description above is the record.