FastMCP vulnerable to reflected XSS in client’s callback page_CVE-2025-62800

{
    "lastseen": "",
    "description": "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.",
    "published": "2025-10-28T21:34:40.392Z",
    "modified": "2025-10-28T21:34:40.392Z",
    "type": "cve",
    "title": "FastMCP vulnerable to reflected XSS in client's callback page",
    "source": "GitHub_M",
    "references": "https://github.com/jlowin/fastmcp/security/advisories/GHSA-mxxr-jv3v-6pgc",
    "id": "CVE-2025-62800",
    "bulletinFamily": "",
    "cwe": [
        "CWE-79"
    ],
    "cvelist": null,
    "sourceData": "jlowin fastmcp < 2.13.0",
    "sourceHref": "",
    "cvss": {
        "score": 5.3,
        "severity": "MEDIUM",
        "vector": "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",
        "version": "4.0"
    },
    "cvss2": [],
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        "baseScore": 0,
        "baseSeverity": "",
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        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
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    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "fastmcp",
    "version": "< 2.13.0",
    "vendor": "jlowin",
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    "ai_score": 0
}