{"cve":"CVE-2026-102271","nvd":{"published":"2026-09-28T21:17:15.110","modified":"2026-10-06T18:36:16.047","status":"Analyzed","description":"PyJWT is a Python implementation of JSON Web Token standards. From 2.4.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because asymmetric-key guard relies on textual markers that are absent from DER encoding. This occurs when an application mixes HMAC and asymmetric algorithms and supplies a DER public key as the shared verification key. As a result, PyJWT uses public DER bytes as an HMAC secret. Consequently, an attacker who knows the public key can forge authenticated HMAC tokens. This issue is fixed in version 2.14.0.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","score":7.4},"cwes":["CWE-347"],"references":["https://github.com/jpadilla/pyjwt/commit/2798504fa2663364573cf2d1043d8d7fef389499","https://github.com/jpadilla/pyjwt/releases/tag/2.14.0","https://github.com/jpadilla/pyjwt/security/advisories/GHSA-p4g4-x82p-q773","https://github.com/jpadilla/pyjwt/security/advisories/GHSA-p4g4-x82p-q773"],"products":["pyjwt_project:pyjwt"],"source":"nvd","synced_at":"2026-10-19T22:56:48.555445741+00:00"},"epss":{"cve":"CVE-2026-102271","score":0.00215,"percentile":0.1176,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-p4g4-x82p-q773","url":"https://osv.dev/vulnerability/GHSA-p4g4-x82p-q773","summary":"PyJWT: Public keys in DER form are accepted as HMAC secrets, bypassing the CVE-2022-29217 guard","modified":"2026-10-01T17:55:49.051187883Z","packages":[{"ecosystem":"PyPI","name":"pyjwt","purl":"pkg:pypi/pyjwt","ranges":[">=2.4.0 <2.14.0"],"fixed":["2.14.0"]}]},{"id":"PYSEC-2026-4149","url":"https://osv.dev/vulnerability/PYSEC-2026-4149","summary":"PyJWT: Public keys in DER form are accepted as HMAC secrets, bypassing the CVE-2022-29217 guard","modified":"2026-10-01T17:45:14.256840962Z","packages":[{"ecosystem":"PyPI","name":"pyjwt","purl":"pkg:pypi/pyjwt","ranges":[">=2.4.0 <2.14.0"],"fixed":["2.14.0"]}]}],"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."]}