CVE-2025-59420

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{"affected": [{"affectedData": [{"product": "authlib", "vendor": "authlib", "versions": [{"status": "affected", "version": "< 1.6.4"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:authlib:authlib:*:*:*:*:*:*:*:*", "matchCriteriaId": "02148BAC-81FF-495B-933A-98B636364E1E", "versionEndExcluding": "1.6.4", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.4, Authlib\u2019s JWS verification accepts tokens that declare unknown critical header parameters (crit), violating RFC 7515 \u201cmust\u2011understand\u201d semantics. An attacker can craft a signed token with a critical header (for example, bork or cnf) that strict verifiers reject but Authlib accepts. In mixed\u2011language fleets, this enables split\u2011brain verification and can lead to policy bypass, replay, or privilege escalation. This issue has been patched in version 1.6.4."}, {"lang": "es", "value": "Authlib es una biblioteca de Python que construye servidores OAuth y OpenID Connect. Antes de la versi\u00f3n 1.6.4, la verificaci\u00f3n JWS de Authlib acepta tokens que declaran par\u00e1metros de encabezado cr\u00edticos (crit) desconocidos, violando la sem\u00e1ntica de 'must-understand' de RFC 7515. Un atacante puede crear un token firmado con un encabezado cr\u00edtico (por ejemplo, bork o cnf) que los verificadores estrictos rechazan pero Authlib acepta. En flotas de lenguaje mixto, esto permite la verificaci\u00f3n de cerebro dividido y puede conducir a la omisi\u00f3n de pol\u00edticas, la repetici\u00f3n o la escalada de privilegios. Este problema ha sido parcheado en la versi\u00f3n 1.6.4."}], "id": "CVE-2025-59420", "lastModified": "2026-10-19T16:10:00.260", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2025-59420", "options": [{"exploitation": "poc"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2025-09-22T18:04:06.580297Z", "version": "2.0.3"}}]}, "published": "2025-09-22T18:15:46.910", "references": [{"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/authlib/authlib/commit/6b1813e4392eb7c168c276099ff7783b176479df"}, {"source": "security-advisories@github.com", "tags": ["Exploit", "Vendor Advisory"], "url": "https://github.com/authlib/authlib/security/advisories/GHSA-9ggr-2464-2j32"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00032.html"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-345"}, {"lang": "en", "value": "CWE-863"}], "source": "security-advisories@github.com", "type": "Secondary"}, {"description": [{"lang": "en", "value": "CWE-345"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "authlib: Authlib RFC violation", "id": "2397460", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2397460"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.5", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N", "status": "draft"}, "cwe": "(CWE-345|CWE-863)", "details": ["No description is available for this CVE."], "mitigation": {"lang": "en:us", "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability."}, "name": "CVE-2025-59420", "package_state": [{"cpe": "cpe:/a:redhat:quay:3", "fix_state": "Affected", "package_name": "quay/quay-rhel8", "product_name": "Red Hat Quay 3"}], "public_date": "2025-09-22T17:28:53Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-59420\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-59420\nhttps://github.com/authlib/authlib/commit/6b1813e4392eb7c168c276099ff7783b176479df\nhttps://github.com/authlib/authlib/security/advisories/GHSA-9ggr-2464-2j32"], "threat_severity": "Important"}

{"created": "2025-09-23T16:08:43.026542+00:00", "updated": "2025-09-23T16:08:43.026596+00:00", "vendors": ["authlib", "authlib$PRODUCT$authlib"]}