{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-107720", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-10-08T17:21:52.975Z", "datePublished": "2026-10-08T21:44:06.843Z", "dateUpdated": "2026-10-08T21:44:06.843Z"}, "containers": {"cna": {"title": "fast-jwt: createVerifier accepts unsigned JWTs when key is '' or null and algorithms is explicitly set", "problemTypes": [{"descriptions": [{"cweId": "CWE-20", "lang": "en", "description": "CWE-20: Improper Input Validation", "type": "CWE"}]}, {"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/nearform/fast-jwt/security/advisories/GHSA-8wpc-h4q6-8fxv", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/nearform/fast-jwt/security/advisories/GHSA-8wpc-h4q6-8fxv"}, {"name": "https://github.com/nearform/fast-jwt/pull/649", "tags": ["x_refsource_MISC"], "url": "https://github.com/nearform/fast-jwt/pull/649"}, {"name": "https://github.com/nearform/fast-jwt/commit/e22a151e83bf6d5e54e281216982d204d5665534", "tags": ["x_refsource_MISC"], "url": "https://github.com/nearform/fast-jwt/commit/e22a151e83bf6d5e54e281216982d204d5665534"}, {"name": "https://github.com/nearform/fast-jwt/releases/tag/v6.3.1", "tags": ["x_refsource_MISC"], "url": "https://github.com/nearform/fast-jwt/releases/tag/v6.3.1"}], "affected": [{"vendor": "nearform", "product": "fast-jwt", "versions": [{"version": "< 6.3.1", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-10-08T21:44:06.843Z"}, "descriptions": [{"lang": "en", "value": "fast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 6.3.1, fast-jwt createVerifier accepts an unsigned JWT when key is an empty string or null and algorithms is a non-empty allowlist. Falsy synchronous keys bypass prepareKeyOrSecret, allowedAlgorithms remains active, hasKey is false, and the empty signature avoids the verifySignature gate. An attacker can therefore submit a token containing arbitrary claims without possessing a signing key, resulting in authentication or authorization bypass. Claim validators still run, and non-empty keys, an empty key without algorithms, and the async key resolver path do not have this behavior. This issue is fixed in version 6.3.1."}], "source": {"advisory": "GHSA-8wpc-h4q6-8fxv", "discovery": "UNKNOWN"}}}}

{}

{"affected": [{"affectedData": [{"product": "fast-jwt", "vendor": "nearform", "versions": [{"status": "affected", "version": "< 6.3.1"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "fast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 6.3.1, fast-jwt createVerifier accepts an unsigned JWT when key is an empty string or null and algorithms is a non-empty allowlist. Falsy synchronous keys bypass prepareKeyOrSecret, allowedAlgorithms remains active, hasKey is false, and the empty signature avoids the verifySignature gate. An attacker can therefore submit a token containing arbitrary claims without possessing a signing key, resulting in authentication or authorization bypass. Claim validators still run, and non-empty keys, an empty key without algorithms, and the async key resolver path do not have this behavior. This issue is fixed in version 6.3.1."}], "id": "CVE-2026-107720", "lastModified": "2026-10-08T22:17:28.227", "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": "2026-10-08T22:17:28.090", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/nearform/fast-jwt/commit/e22a151e83bf6d5e54e281216982d204d5665534"}, {"source": "security-advisories@github.com", "url": "https://github.com/nearform/fast-jwt/pull/649"}, {"source": "security-advisories@github.com", "url": "https://github.com/nearform/fast-jwt/releases/tag/v6.3.1"}, {"source": "security-advisories@github.com", "url": "https://github.com/nearform/fast-jwt/security/advisories/GHSA-8wpc-h4q6-8fxv"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-20"}, {"lang": "en", "value": "CWE-347"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{}