{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-102266", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-09-28T20:11:16.658Z", "datePublished": "2026-09-28T20:21:26.164Z", "dateUpdated": "2026-09-28T20:21:26.164Z"}, "containers": {"cna": {"title": "PyJWK accepts empty HMAC keys, bypassing PyJWT's empty-key validation", "problemTypes": [{"descriptions": [{"cweId": "CWE-347", "lang": "en", "description": "CWE-347: Improper Verification of Cryptographic Signature", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.4, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N", "version": "3.1"}}], "references": [{"name": "https://github.com/jpadilla/pyjwt/security/advisories/GHSA-9j54-fg26-wv3r", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/jpadilla/pyjwt/security/advisories/GHSA-9j54-fg26-wv3r"}, {"name": "https://github.com/jpadilla/pyjwt/commit/f91ed44dd65baaf457f4b3353ed35e98a753934c", "tags": ["x_refsource_MISC"], "url": "https://github.com/jpadilla/pyjwt/commit/f91ed44dd65baaf457f4b3353ed35e98a753934c"}, {"name": "https://github.com/jpadilla/pyjwt/releases/tag/2.14.0", "tags": ["x_refsource_MISC"], "url": "https://github.com/jpadilla/pyjwt/releases/tag/2.14.0"}], "affected": [{"vendor": "jpadilla", "product": "pyjwt", "versions": [{"version": ">= 2.13.0, < 2.14.0", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-09-28T20:21:26.164Z"}, "descriptions": [{"lang": "en", "value": "PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.from_jwk is affected because PyJWK verification path used the decoded key without applying prepare_key validation. This occurs when a trusted JWK Set contains an oct entry with an empty k value. As a result, an attacker signs an HMAC token with the same zero-length key accepted by PyJWT. Consequently, forged token can carry arbitrary authenticated claims. This issue is fixed in version 2.14.0."}], "source": {"advisory": "GHSA-9j54-fg26-wv3r", "discovery": "UNKNOWN"}}}}

{}

{"affected": [{"affectedData": [{"product": "pyjwt", "vendor": "jpadilla", "versions": [{"status": "affected", "version": ">= 2.13.0, < 2.14.0"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.from_jwk is affected because PyJWK verification path used the decoded key without applying prepare_key validation. This occurs when a trusted JWK Set contains an oct entry with an empty k value. As a result, an attacker signs an HMAC token with the same zero-length key accepted by PyJWT. Consequently, forged token can carry arbitrary authenticated claims. This issue is fixed in version 2.14.0."}], "id": "CVE-2026-102266", "lastModified": "2026-09-28T21:17:14.257", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.4, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 5.2, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-09-28T21:17:14.257", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/jpadilla/pyjwt/commit/f91ed44dd65baaf457f4b3353ed35e98a753934c"}, {"source": "security-advisories@github.com", "url": "https://github.com/jpadilla/pyjwt/releases/tag/2.14.0"}, {"source": "security-advisories@github.com", "url": "https://github.com/jpadilla/pyjwt/security/advisories/GHSA-9j54-fg26-wv3r"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-347"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[2.13.0,2.14.0)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "pyjwt", "source": "cna", "vendor": "jpadilla"}, "product": "pyjwt", "vendor": "jpadilla"}], "created": "2026-09-28T21:45:06.764468+00:00", "updated": "2026-09-28T22:15:08.592048+00:00", "vendors": ["jpadilla", "jpadilla$PRODUCT$pyjwt"]}