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

{
  "id": "b8b4d32ecbb958a28a67db01f4ee8448e10cd32b7fb5859083c399333767a570",
  "url": "https://osv.dev/vulnerability/CVE-2026-40911",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "WWBN AVideo YPTSocket WebSocket Broadcast Relay Leads to Unauthenticated Cross-User JavaScript Execution via Client-Side eval() Sinks",
    "summary": "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.",
    "evidence": "osv:CVE-2026-40911",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-40911",
      "aliases": [
        "CVE-2026-40911",
        "GHSA-gph2-j4c9-vhhr"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/wwbn/avideo",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "c08694bf6264eb4decceb78c711baee2609b4efd"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:wwbn:avideo:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "29.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "c08694bf6264eb4decceb78c711baee2609b4efd"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "29.0",
            "26.0",
            "25.0",
            "24.0",
            "22.0",
            "21.0",
            "18.0",
            "14.3.1",
            "14.3",
            "12.4",
            "11.6",
            "11.5",
            "11.1.1",
            "11.1",
            "11",
            "10.8",
            "8.9.1",
            "8.9",
            "8.7",
            "8.6",
            "8.5",
            "8.1",
            "7.8",
            "7.7",
            "7.6",
            "7.4",
            "7.3",
            "7.2",
            "4.0",
            "3.4",
            "2.7",
            "2.2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-40911.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:34.375527419Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40911.json",
        "https://github.com/WWBN/AVideo/security/advisories/GHSA-gph2-j4c9-vhhr",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-40911",
        "https://github.com/WWBN/AVideo/commit/c08694bf6264eb4decceb78c711baee2609b4efd"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-94"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40911.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-40911",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 501296,
  "published_at": "2026-04-21T19:55:37.195+00:00"
}