CVE-2026-48523

{"id": "CVE-2026-48523", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.4, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "LOW"}, "impactScore": 2.5, "exploitabilityScore": 2.8}]}, "published": "2026-05-28T16:16:29.280", "references": [{"url": "https://github.com/jpadilla/pyjwt/security/advisories/GHSA-jq35-7prp-9v3f", "tags": ["Exploit", "Vendor Advisory"], "source": "security-advisories@github.com"}, {"url": "https://github.com/jpadilla/pyjwt/security/advisories/GHSA-jq35-7prp-9v3f", "tags": ["Exploit", "Vendor Advisory"], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-347"}]}], "descriptions": [{"lang": "en", "value": "PyJWT is a JSON Web Token implementation in Python. From 2.9.0 to 2.12.1, there is a verifier-side algorithm allow-list bypass when jwt.decode() or jwt.decode_complete() are called with a PyJWK key. The token header alg is checked against the caller-supplied algorithms allow-list, but signature verification is performed with the algorithm bound to the PyJWK object instead of the header algorithm. An attacker who controls a registered JWK/JWKS private key can sign with a disallowed algorithm, advertise an allowed algorithm in the JWT header, and still be accepted. The issue affects the documented PyJWKClient.get_signing_key_from_jwt(...) flow. This vulnerability is fixed in 2.13.0."}], "lastModified": "2026-06-01T17:44:48.617", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:pyjwt_project:pyjwt:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "AD0759FF-955F-482B-9EB8-C2F445D540E4", "versionEndExcluding": "2.12.1", "versionStartIncluding": "2.9.0"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}