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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

10.0 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS

• CVE-2026-40911: 0.65% estimated exploitation activity in the next 30 days; percentile 50.97 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary 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. Details Token issuance is unauthenticated plugin/YPTSocket/getWebSocket.json.php:11-21 returns a token to anyone whose request reaches the endpoint — the only check is that the plugin is enabled: getEncryptedInfo() in plugin/YPTSocket/functions.php:3-16 populates fromusersid = User::getId() (0 for guests) and isAdmin…

Published by the source

14 Apr 2026, 22:50 UTC

Last modified by the source

24 Apr 2026, 20:30 UTC

Source last checked

26 Oct 2026, 14:39 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-gph2-j4c9-vhhr

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# Patch Next advisory brief: CVE-2026-40911

Advisory: WWBN AVideo YPTSocket WebSocket Broadcast Relay Leads to Unauthenticated Cross-User JavaScript Execution via Client-Side eval() Sinks
IDs: CVE-2026-40911, GHSA-gph2-j4c9-vhhr
Record: https://patchnext.com/advisories/cve-2026-40911 (revision 1, source checked 26 Oct 2026, 14:39 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 10.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist wwbn/avideo: affected <= 29.0

## Suggested inspection (read-only)
- Packagist wwbn/avideo: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on wwbn/avideo.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-gph2-j4c9-vhhr (GitHub-reviewed advisory GHSA-gph2-j4c9-vhhr lists affected ranges: Packagist wwbn/avideo >=0 <=29.0)

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