{"answers":{"affected":"2 open source packages ship an affected version, including fast-jwt. It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-35042 exists.","fix":"No fix has been published for CVE-2026-35042 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-35042 is a high-severity vulnerability in nearform fast-jwt, published on 6 Apr 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-2026-35042 and fix it if it is affected.\n\nWhat it is: CVE-2026-35042 is a high-severity vulnerability in nearform fast-jwt, published on 6 Apr 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-2026-35042 exists.\n\nAffected packages and fixed versions:\n- fast-jwt (npm): affected all versions up to 6.1.0; no fix listed\n- fast-jwt (npm): affected all versions up to 6.1.0; no fix listed\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-2026-35042/ (Markdown: https://insights.sbomify.com/CVE-2026-35042/index.md)","id":"CVE-2026-35042","markdown":"https://insights.sbomify.com/CVE-2026-35042/index.md","name":"CVE-2026-35042","record":{"aliases":["GHSA-hm7r-c7qw-ghp6"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"JavaScript JWT library","requires_auth":"none","summary":"Attackers can bypass JWT security checks by using unknown critical header extensions, potentially leading to unauthorized access.","user_interaction":"not_required","vuln_class":"security_feature_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"fast-jwt","vendor":"nearform"}],"cvss":{"score":7.5,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","version":"3.1"},"cwes":[{"id":"CWE-636","name":"Not Failing Securely"},{"id":"CWE-345","name":"Insufficient Verification of Data Authenticity"}],"description":"fast-jwt provides fast JSON Web Token (JWT) implementation. In 6.1.0 and earlier, fast-jwt does not validate the crit (Critical) Header Parameter defined in RFC 7515 §4.1.11. When a JWS token contains a crit array listing extensions that fast-jwt does not understand, the library accepts the token instead of rejecting it. This violates the MUST requirement in the RFC.","ecosystems":["npm"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":false,"headline":"fast-jwt accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)","id":"CVE-2026-35042","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":null,"products":[],"type":"security_feature_bypass","year":"2026"},"n_packages":2,"n_references":2,"next":{"headline":"BentoML: command injection in cloud deployment setup script (deployment.py)","id":"CVE-2026-35043"},"packages":[{"ecosystem":"npm","fixed":[],"introduced":["0"],"last_affected":["6.1.0"],"package":"fast-jwt","purl":null,"source":"GHSA-hm7r-c7qw-ghp6"},{"ecosystem":"npm","fixed":[],"introduced":["0"],"last_affected":["6.1.0"],"package":"fast-jwt","purl":"pkg:npm/fast-jwt","source":"GHSA-hm7r-c7qw-ghp6"}],"prev":{"headline":"ReDoS in fast-jwt when using RegExp in allowed* leading to CPU exhaustion during token verification","id":"CVE-2026-35041"},"products":["fast-jwt"],"published":"2026-04-06","related":[{"cvss_score":9.1,"headline":"fast-jwt has an incomplete fix for CVE-2023-48223: JWT Algorithm Confusion via Whitespace-Prefixed RSA Public Key","id":"CVE-2026-34950","kev_date_added":null,"published":"2026-04-06"},{"cvss_score":9.1,"headline":"fast-jwt: Cache Confusion via cacheKeyBuilder Collisions Can Return Claims From a Different Token (Identity/Authorization Mixup)","id":"CVE-2026-35039","kev_date_added":null,"published":"2026-04-06"},{"cvss_score":5.9,"headline":"fast-jwt JWT Algorithm Confusion","id":"CVE-2023-48223","kev_date_added":null,"published":"2023-11-20"},{"cvss_score":5.3,"headline":"fast-jwt: Stateful RegExp (/g or /y) causes non-deterministic allowed-claim validation (logical DoS)","id":"CVE-2026-35040","kev_date_added":null,"published":"2026-04-09"},{"cvss_score":4.2,"headline":"ReDoS in fast-jwt when using RegExp in allowed* leading to CPU exhaustion during token verification","id":"CVE-2026-35041","kev_date_added":null,"published":"2026-04-09"}],"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":"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":"yes","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-04-07","vendors":["nearform"]},"summary":"Attackers can bypass JWT security checks by using unknown critical header extensions, potentially leading to unauthorized access.","url":"https://insights.sbomify.com/CVE-2026-35042/"}