Authlib is vulnerable to Denial of Service via Oversized JOSE Segments_CVE-2025-61920

{
    "lastseen": "",
    "description": "Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.5, Authlib\u2019s JOSE implementation accepts unbounded JWS/JWT header and signature segments. A remote attacker can craft a token whose base64url\u2011encoded header or signature spans hundreds of megabytes. During verification, Authlib decodes and parses the full input before it is rejected, driving CPU and memory consumption to hostile levels and enabling denial of service. Version 1.6.5 patches the issue. Some temporary workarounds are available. Enforce input size limits before handing tokens to Authlib and/or use application-level throttling to reduce amplification risk.",
    "published": "2025-10-10T19:25:07.679Z",
    "modified": "2025-10-10T19:25:07.679Z",
    "type": "cve",
    "title": "Authlib is vulnerable to Denial of Service via Oversized JOSE Segments",
    "source": "GitHub_M",
    "references": "https://github.com/authlib/authlib/security/advisories/GHSA-pq5p-34cr-23v9\nhttps://github.com/authlib/authlib/commit/867e3f87b072347a1ae9cf6983cc8bbf88447e5e",
    "id": "CVE-2025-61920",
    "bulletinFamily": "",
    "cwe": [
        "CWE-20",
        "CWE-400",
        "CWE-770"
    ],
    "cvelist": null,
    "sourceData": "authlib authlib < 1.6.5",
    "sourceHref": "",
    "cvss": {
        "score": 7.5,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
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        "baseScore": 0,
        "baseSeverity": "",
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        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "authlib",
    "version": "< 1.6.5",
    "vendor": "authlib",
    "ai_description": "",
    "ai_severity": "",
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    "ai_score": 0
}