CVE-2026-40911
Received Received - Intake
Remote Code Execution via Unsanitized WebSocket Messages in WWBN AVideo

Publication date: 2026-04-21

Last updated on: 2026-04-27

Assigner: GitHub, Inc.

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.
CVSS Scores
EPSS Scores
Probability:
Percentile:
Meta Information
Published
2026-04-21
Last Modified
2026-04-27
Generated
2026-05-07
AI Q&A
2026-04-22
EPSS Evaluated
2026-05-05
NVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
wwbn avideo to 29.0 (inc)
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-94 The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability exists in the WWBN AVideo platform, specifically in versions 29.0 and prior. The YPTSocket plugin's WebSocket server relays attacker-supplied JSON message bodies to all connected clients without sanitizing the 'msg' or 'callback' fields.

On the client side, the script 'plugin/YPTSocket/script.js' uses two eval() functions that directly execute these unsanitized fields. Because tokens for anonymous visitors are minted and never revalidated beyond decryption, an unauthenticated attacker can broadcast arbitrary JavaScript code.

This malicious JavaScript executes in the origin of every connected user, including administrators, enabling universal account takeover, session theft, and execution of privileged actions.


How can this vulnerability impact me? :

The vulnerability allows an unauthenticated attacker to execute arbitrary JavaScript code in the context of every connected user, including administrators.

  • Universal account takeover
  • Session theft
  • Execution of privileged actions on behalf of users

What immediate steps should I take to mitigate this vulnerability?

To mitigate this vulnerability, you should update the WWBN AVideo platform to a version that includes the fix, specifically the commit c08694bf6264eb4decceb78c711baee2609b4efd or later.

Since the vulnerability involves unsafe use of eval() in the YPTSocket plugin's WebSocket server, avoid using versions 29.0 and prior.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

Detection of this vulnerability involves monitoring WebSocket traffic for suspicious JSON messages containing the fields `msg.autoEvalCodeOnHTML` or `callback` that are relayed without sanitization.

You can inspect WebSocket messages on your network or system by capturing traffic and filtering for these fields to identify potential exploitation attempts.

  • Use a network packet capture tool like tcpdump or Wireshark to capture WebSocket traffic on the relevant ports.
  • Example tcpdump command to capture WebSocket traffic (assuming default HTTP port 80 or HTTPS port 443):
  • tcpdump -i <interface> -A -s 0 'tcp port 80 or tcp port 443' | grep -E 'autoEvalCodeOnHTML|callback'
  • Use browser developer tools to monitor WebSocket frames in real time and look for JSON messages containing `msg.autoEvalCodeOnHTML` or suspicious `callback` values.
  • On the server, review WebSocket logs or enable verbose logging in the YPTSocket plugin to detect incoming messages with these fields.

Since the vulnerability involves unauthenticated token issuance and message broadcasting, monitoring for unexpected WebSocket connections and broadcast messages from anonymous users can also help detect exploitation.


How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:

This vulnerability allows an unauthenticated attacker to execute arbitrary JavaScript in the context of every connected user, including administrators. This can lead to universal account takeover, session theft, and execution of privileged actions.

Such security breaches can result in unauthorized access to sensitive personal data and administrative controls, which may violate data protection regulations like GDPR and HIPAA that require safeguarding user data and ensuring system integrity.

Therefore, the vulnerability poses a significant risk to compliance with these standards by potentially exposing confidential information and compromising system security.


Ask Our AI Assistant
Need more information? Ask your question to get an AI reply (Powered by our expertise)
0/70
EPSS Chart