{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "716e50dae0b445fb7fd0251725fc827c045d5fdd"
            }
          ],
          "repo": "https://github.com/jlowin/fastmcp",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-mxxr-jv3v-6pgc"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-79"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/62xxx/CVE-2025-62800.json"
  },
  "details": "FastMCP is the standard framework for building MCP applications. Versions prior to 2.13.0 have a reflected cross-site scripting vulnerability in the OAuth client callback page (oauth_callback.py) where unescaped user-controlled values are inserted into the generated HTML, allowing arbitrary JavaScript execution in the callback server origin. The issue is fixed in version 2.13.0.",
  "id": "CVE-2025-62800",
  "modified": "2026-03-13T21:50:56.647123269Z",
  "published": "2025-10-28T21:34:40.392Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/62xxx/CVE-2025-62800.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/jlowin/fastmcp/security/advisories/GHSA-mxxr-jv3v-6pgc"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-62800"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "FastMCP vulnerable to reflected XSS in client's callback page"
}