{"id":"CVE-2026-102271","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-102271","generatedAt":"2026-10-28T02:59:24.262Z","title":"Consequently, an attacker who knows the public key can forge authenticated HMAC tokens.","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.","published":"2026-09-28T21:17:15.000Z","lastModified":"2026-10-06T18:36:16.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":7.4,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"},"cwe":["CWE-347"],"affected":["pyjwt project/pyjwt"],"epss":{"score":0.00215,"percentile":0.11767,"date":"2026-10-26","history":[{"date":"2026-09-29","score":0.00175,"percentile":0.06181}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.21%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[{"kind":"new","label":"New CVE","at":"2026-09-28T21:17:15.000Z","detail":{"score":"7.4","severity":"HIGH","publishedAt":"2026-09-28T21:17:15.110Z"},"summary":"New CVE, high severity (CVSS 7.4)."}],"references":[{"url":"https://github.com/jpadilla/pyjwt/commit/2798504fa2663364573cf2d1043d8d7fef389499","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/jpadilla/pyjwt/releases/tag/2.14.0","tags":["Product","Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/jpadilla/pyjwt/security/advisories/GHSA-p4g4-x82p-q773","tags":["Exploit","Patch","Vendor Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/jpadilla/pyjwt/security/advisories/GHSA-p4g4-x82p-q773","tags":["Exploit","Patch","Vendor Advisory"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-102271","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}