CVE-2026-43874 – WWBN AVideo: Incomplete Fix for YPTSocket autoEvalCodeOnHTML Strip: Unauthenticated Cross-User JavaScript Execution via `$msg[‘json’]` Relay Bypass

CVE ID :CVE-2026-43874

Published : May 11, 2026, 9:19 p.m. | 42 minutes ago

Description :WWBN AVideo is an open source video platform. In versions up to and including 29.0, the server-side mitigation for the YPTSocket autoEvalCodeOnHTML eval sink (from CVE-2026-40911) only strips the payload when it sits under $json[‘msg’], but the relay function msgToResourceId() selects the outbound message from $msg[‘json’] before $msg[‘msg’]. An unauthenticated attacker can obtain a WebSocket token from plugin/YPTSocket/getWebSocket.json.php, connect to the WebSocket server, and send a message with autoEvalCodeOnHTML nested under a top-level json field — the strip branch is skipped, the relay delivers the payload verbatim to any logged-in user identified by to_users_id, and the client script runs it through eval(). Commit 9f3006f9a89a34daa67a83c6ad35f450cb91fcce contains an updated fix.

Severity: 7.2 | HIGH

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