{"cve":"CVE-2026-48523","nvd":{"published":"2026-05-28T16:16:29.280","modified":"2026-10-25T23:10:00.167","status":"Analyzed","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","score":5.4},"cwes":["CWE-347"],"references":["https://github.com/jpadilla/pyjwt/security/advisories/GHSA-jq35-7prp-9v3f","https://github.com/jpadilla/pyjwt/security/advisories/GHSA-jq35-7prp-9v3f"],"products":["pyjwt_project:pyjwt"],"source":"nvd","synced_at":"2026-10-25T23:44:33.281319194+00:00"},"epss":{"cve":"CVE-2026-48523","score":0.00127,"percentile":0.02324,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-jq35-7prp-9v3f","url":"https://osv.dev/vulnerability/GHSA-jq35-7prp-9v3f","summary":"PyJWT: Algorithm allow-list bypass when decoding with `PyJWK` / `PyJWKClient` keys","modified":"2026-09-10T03:51:08.776007275Z","packages":[{"ecosystem":"PyPI","name":"pyjwt","purl":"pkg:pypi/pyjwt","ranges":[">=2.9.0 <2.13.0"],"fixed":["2.13.0"]}]},{"id":"PYSEC-2026-176","url":"https://osv.dev/vulnerability/PYSEC-2026-176","summary":"","modified":"2026-06-02T12:15:10.358230706Z","packages":[{"ecosystem":"PyPI","name":"pyjwt","purl":"pkg:pypi/pyjwt","ranges":[">=2.9.0 <2.12.1"],"fixed":["2.12.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}