Authlib OAuth 2.0 authorization endpoint open redirects to attacker-controlled redirect_uri on unsupported response_type_CVE-2026-41479

{
    "lastseen": "",
    "description": "Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to 1.6.10 and 1.7.1, Authlib's OAuth 2.0 authorization endpoint can be turned into an unauthenticated open redirect when a request uses an unsupported response_type and supplies an attacker-controlled redirect_uri. The vulnerable behavior happens before client lookup and before any redirect URI validation. As a result, an attacker does not need a valid client registration, an authenticated user, or any prior state. A single request to the authorization endpoint is enough to obtain a 302 Location response to an arbitrary attacker-controlled URL. This vulnerability is fixed in 1.6.10 and 1.7.1.",
    "published": "2026-06-22T20:35:13.699Z",
    "modified": "2026-06-22T20:35:13.699Z",
    "type": "cve",
    "title": "Authlib OAuth 2.0 authorization endpoint open redirects to attacker-controlled redirect_uri on unsupported response_type",
    "source": "GitHub_M",
    "references": "https://github.com/authlib/authlib/security/advisories/GHSA-w8p2-r796-3vmq\nhttps://github.com/authlib/authlib/commit/3be08468201a7766a93012ce149ea12822cab096",
    "id": "CVE-2026-41479",
    "bulletinFamily": "",
    "cwe": [
        "CWE-601"
    ],
    "cvelist": null,
    "sourceData": "authlib authlib < 1.6.10\nauthlib authlib = 1.7.0",
    "sourceHref": "",
    "cvss": {
        "score": 5.4,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N",
        "version": "3.1"
    },
    "cvss2": [],
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        "baseScore": 0,
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        "confidentialityImpact": "",
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        "availabilityImpact": "",
        "cvssV3": {
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    },
    "href": "",
    "category_name": "CVE",
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    "product": "authlib",
    "version": "< 1.6.10",
    "vendor": "authlib",
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    "ai_score": 0
}