{"answers":{"affected":"3 open source packages ship an affected version, including pyjwt and PyJWT. It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-102266 exists.","fix":"Upgrade pyjwt to 2.14.0 or later.","what":"CVE-2026-102266 is a high-severity authentication bypass vulnerability in jpadilla pyjwt, published on 28 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-102266 and fix it if it is affected.\n\nWhat it is: CVE-2026-102266 is a high-severity authentication bypass vulnerability in jpadilla pyjwt, published on 28 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-102266 exists.\n\nAffected packages and fixed versions:\n- pyjwt (PyPI): affected from 2.13.0; fixed in 2.14.0\n- pyjwt (PyPI): affected from 2.13.0; fixed in 2.14.0\n- PyJWT (PyPI): affected from 2.13.0; fixed in 2.14.0\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-102266/ (Markdown: https://insights.sbomify.com/CVE-2026-102266/index.md)","id":"CVE-2026-102266","markdown":"https://insights.sbomify.com/CVE-2026-102266/index.md","name":"CVE-2026-102266","record":{"aliases":["AZL-105239","CLEANSTART-2026-OQ39308","CLEANSTART-2026-XF88803","DEBIAN-CVE-2026-102266","ECHO-4dcd-bf8f-9933","GHSA-9j54-fg26-wv3r","MINI-356v-j25g-ff44","MINI-6c27-54hw-m4mj","MINI-7rrv-qmwc-prhf","MINI-7wj6-rc2w-77pj","MINI-8v62-976x-22v8","MINI-f27x-969m-42c3","MINI-g49m-8hxh-wjjm","MINI-ghxx-2gc2-262j","MINI-h77w-j52v-m8j2","MINI-mq7x-4fc8-9qm9","MINI-px6v-x9hf-m79j","MINI-rh8r-2cf9-x3w7","MINI-w436-g5cf-vv4q","MINI-wfcp-g4w7-qvcv","PYSEC-2026-4143","ROOT-APP-PYPI-CVE-2026-102266","UBUNTU-CVE-2026-102266"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["security_bypass","privilege_escalation"],"network_reachable":"yes","non_default_config":false,"product_category":"Python JWT library","requires_auth":"none","summary":"Attackers can forge JWT tokens with arbitrary claims by exploiting empty HMAC key validation in PyJWK, bypassing authentication.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"pyjwt","vendor":"pyjwt_project"}],"cvss":{"score":7.4,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","version":"3.1"},"cwes":[{"id":"CWE-347","name":"Improper Verification of Cryptographic Signature"}],"description":"PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.from_jwk is affected because PyJWK verification path used the decoded key without applying prepare_key validation. This occurs when a trusted JWK Set contains an oct entry with an empty k value. As a result, an attacker signs an HMAC token with the same zero-length key accepted by PyJWT. Consequently, forged token can carry arbitrary authenticated claims. This issue is fixed in version 2.14.0.","ecosystems":["PyPI"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"PyJWK accepts empty HMAC keys, bypassing PyJWT's empty-key validation","id":"CVE-2026-102266","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":null,"products":[],"type":"auth_bypass","year":"2026"},"n_packages":3,"n_references":3,"next":{"headline":"PyJWT: PyJWKClient follows redirects when fetching JWKS","id":"CVE-2026-102267"},"packages":[{"ecosystem":"PyPI","fixed":["2.14.0"],"introduced":["2.13.0"],"last_affected":[],"package":"PyJWT","purl":null,"source":"GHSA-9j54-fg26-wv3r"},{"ecosystem":"PyPI","fixed":["2.14.0"],"introduced":["2.13.0"],"last_affected":[],"package":"pyjwt","purl":"pkg:pypi/pyjwt","source":"GHSA-9j54-fg26-wv3r"},{"ecosystem":"PyPI","fixed":["2.14.0"],"introduced":["2.13.0"],"last_affected":[],"package":"pyjwt","purl":"pkg:pypi/pyjwt","source":"PYSEC-2026-4143"}],"prev":{"headline":"PyJWT: Uncaught RecursionError in jwt.decode() on deeply nested token header","id":"CVE-2026-102265"},"products":["pyjwt"],"published":"2026-09-28","related":[{"cvss_score":9.1,"headline":"PyJWT: Asymmetric-PEM detection bypass: whitespace/line-ending-mutated public keys skip the HS/asymmetric confusion guard","id":"CVE-2026-102268","kev_date_added":null,"published":"2026-09-28"},{"cvss_score":7.5,"headline":"PyJWT accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)","id":"CVE-2026-32597","kev_date_added":null,"published":"2026-03-12"},{"cvss_score":7.4,"headline":"PyJWT: PyJWKClient follows redirects when fetching JWKS","id":"CVE-2026-102267","kev_date_added":null,"published":"2026-09-28"},{"cvss_score":7.4,"headline":"PyJWT: Public keys in DER form are accepted as HMAC secrets, bypassing the CVE-2022-29217 guard","id":"CVE-2026-102271","kev_date_added":null,"published":"2026-09-28"},{"cvss_score":7.4,"headline":"PyJWT BOM Bypass","id":"CVE-2026-102272","kev_date_added":null,"published":"2026-09-28"},{"cvss_score":7.4,"headline":"PyJWT accepts public JWK containers as HMAC secrets","id":"CVE-2026-102273","kev_date_added":null,"published":"2026-09-28"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"PyPA Advisory Database","prefix":"PYSEC"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"poc","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-09-29","vendors":["jpadilla"]},"summary":"Attackers can forge JWT tokens with arbitrary claims by exploiting empty HMAC key validation in PyJWK, bypassing authentication.","url":"https://insights.sbomify.com/CVE-2026-102266/"}