{"id":"CVE-2026-40911","aliases":["GHSA-gph2-j4c9-vhhr"],"url":"https://o3.security/vulnerability/CVE-2026-40911","summary":"WWBN AVideo YPTSocket WebSocket Broadcast Relay Leads to Unauthenticated Cross-User JavaScript Execution via Client-Side eval() Sinks","details":"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.","published":"2026-04-21T19:55:37.195Z","modified":"2026-08-07T11:50:17.782858018Z","cvss":{"score":10,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"wwbn/avideo","fixedVersion":null}],"fix":{"url":"https://github.com/WWBN/AVideo/commit/c08694bf6264eb4decceb78c711baee2609b4efd","label":"WWBN/AVideo@c08694b"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40911.json"},{"type":"ADVISORY","url":"https://github.com/WWBN/AVideo/security/advisories/GHSA-gph2-j4c9-vhhr"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-40911"},{"type":"FIX","url":"https://github.com/WWBN/AVideo/commit/c08694bf6264eb4decceb78c711baee2609b4efd"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:50:17.782858018Z"}}