Open WebUI: Same-origin XSS to account takeover via terminal file-preview iframe hardcoding allow-same-origin

{
  "id": "8f68a4db7e6358d6366ab9e7bee6a80a17ab292f6fa4f7ebdedbc1d74beca48d",
  "url": "https://osv.dev/vulnerability/CVE-2026-70486",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Open WebUI: Same-origin XSS to account takeover via terminal file-preview iframe hardcoding allow-same-origin",
    "summary": "Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.0 until 0.11.0, the terminal file-preview serveUrl iframe branch always granted allow-same-origin together with allow-scripts for HTML files served from the application origin. Any authenticated user with access to a configured terminal server could cause script in a previewed file to run in the Open WebUI origin, read the victim's session token from localStorage, and take over the account, with possible server-side code execution if the victim was an admin or held workspace.functions. This issue is fixed in 0.11.0.",
    "evidence": "osv:CVE-2026-70486",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-70486",
      "aliases": [
        "CVE-2026-70486",
        "GHSA-3xpf-xq7r-v8c5",
        "PYSEC-2026-3641"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/open-webui/open-webui",
              "type": "GIT",
              "events": [
                {
                  "introduced": "f31768e20e5c6b4f6da0ef657877298b359936cf"
                },
                {
                  "fixed": "f9590b8017199e56d5e953657e6498e3cef1d246"
                },
                {
                  "fixed": "65a5fad7b97db99d490d81f4e0860282c3a4543c"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0.9.0"
                      },
                      {
                        "fixed": "0.11.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "65a5fad7b97db99d490d81f4e0860282c3a4543c"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "f9590b8017199e56d5e953657e6498e3cef1d246"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v0.11.0"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.10.2",
            "v0.10.1",
            "v0.10.0",
            "v0.9.5",
            "v0.9.4",
            "v0.9.3",
            "v0.9.2",
            "v0.9.1",
            "v0.9.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-70486.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:50.574297623Z",
      "provider": "osv",
      "references": [
        "https://github.com/open-webui/open-webui/releases/tag/v0.11.0",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/70xxx/CVE-2026-70486.json",
        "https://github.com/open-webui/open-webui/security/advisories/GHSA-3xpf-xq7r-v8c5",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-70486",
        "https://github.com/open-webui/open-webui/commit/65a5fad7b97db99d490d81f4e0860282c3a4543c",
        "https://github.com/open-webui/open-webui/pull/26907"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-1021",
          "CWE-79"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/70xxx/CVE-2026-70486.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-70486",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 518739,
  "published_at": "2026-08-04T20:01:55.319+00:00"
}