{"answers":{"affected":"","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-75509 exists.","fix":"Upgrade to a fixed version.","what":"CVE-2026-75509 is a medium-severity authentication bypass vulnerability in authlib joserfc, published on 24 Aug 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-2026-75509 and fix it if it is affected.\n\nWhat it is: CVE-2026-75509 is a medium-severity authentication bypass vulnerability in authlib joserfc, published on 24 Aug 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-2026-75509 exists.\n\nAffected product: authlib joserfc. No package-level version data is available, so check the vendor advisory linked from the reference page.\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-2026-75509/ (Markdown: https://insights.sbomify.com/CVE-2026-75509/index.md)","id":"CVE-2026-75509","markdown":"https://insights.sbomify.com/CVE-2026-75509/index.md","name":"CVE-2026-75509","record":{"aliases":["CLEANSTART-2026-JQ90440","CLEANSTART-2026-ZW66973","DEBIAN-CVE-2026-75509","GHSA-r74j-q665-7rpj","UBUNTU-CVE-2026-75509"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Python JOSE library","requires_auth":"none","summary":"Attackers can bypass JWT issuer validation by using array-valued claims, allowing unauthorized access in applications using joserfc.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[],"cvss":{"score":6.5,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","version":"3.1"},"cwes":[{"id":"CWE-345","name":"Insufficient Verification of Data Authenticity"},{"id":"CWE-290","name":"Authentication Bypass by Spoofing"}],"description":"joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to version 1.7.3, JWTClaimsRegistry applies membership matching to list-valued iss and sub claims, allowing an array-valued iss that contains the expected issuer to pass an intended equality check and enabling issuer-validation bypass. This issue is fixed in version 1.7.3.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"joserfc claim-validation bypass via array-typed single-string claims (iss/sub/jti)","id":"CVE-2026-75509","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"auth_bypass","year":"2026"},"n_packages":0,"n_references":2,"next":{"headline":"Novu: Stored XSS in In-App Inbox via notification redirect.url javascript: scheme","id":"CVE-2026-75510"},"packages":[],"prev":{"headline":"GraphQL-core: Denial of service via comment tokens bypassing the parser's max_tokens limit","id":"CVE-2026-75508"},"products":["joserfc"],"published":"2026-08-24","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"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":"partial"},"state":"PUBLISHED","updated":"2026-08-25","vendors":["authlib"]},"summary":"Attackers can bypass JWT issuer validation by using array-valued claims, allowing unauthorized access in applications using joserfc.","url":"https://insights.sbomify.com/CVE-2026-75509/"}