{"answers":{"affected":"2 open source packages ship an affected version, including fastify. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-76169 in the wild and no public exploit code.","fix":"Upgrade fastify to 5.12.2 or later.","what":"CVE-2026-76169 is a high-severity authentication bypass vulnerability in fastify, published on 4 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-2026-76169 and fix it if it is affected.\n\nWhat it is: CVE-2026-76169 is a high-severity authentication bypass vulnerability in fastify, published on 4 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-76169 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- fastify (npm): affected from 4.0.0; fixed in 5.12.2\n- fastify (npm): affected from 4.0.0; fixed in 5.12.2\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-2026-76169/ (Markdown: https://insights.sbomify.com/CVE-2026-76169/index.md)","id":"CVE-2026-76169","markdown":"https://insights.sbomify.com/CVE-2026-76169/index.md","name":"CVE-2026-76169","record":{"aliases":["CLSA-2026-1790863084","CLSA-2026-1790871227","CLSA-2026-1790889495","GHSA-p68q-wchp-6fh7","MINI-v23q-6ffp-9r2f"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["data_read","security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Node.js web framework","requires_auth":"none","summary":"An unauthenticated attacker can bypass authentication hooks to read protected responses from encapsulated not-found handlers via malformed URLs.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"openjs","cpe":[{"product":"fastify","vendor":"fastify"}],"cvss":{"score":7.5,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","version":"3.1"},"cwes":[{"id":"CWE-288","name":"Authentication Bypass Using an Alternate Path or Channel"}],"description":"fastify versions \u003e= 4.0.0 and before 5.12.2 can route a malformed URL sent under one plugin prefix to the custom not-found handler of a different sibling plugin, and invoke it without the preHandler hook declared for that handler. The internal not-found router for encapsulated handlers dispatches malformed paths through a single shared handler pointer before URL decoding, ignoring the prefix and skipping the selected handler's normal lifecycle. An unauthenticated attacker can therefore reach an authentication-protected private fallback through an unrelated public prefix and read its full response, bypassing the authentication hook and breaking prefix encapsulation. Users should upgrade to fastify 5.12.2 or later.","ecosystems":["npm"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"fastify vulnerable to authentication bypass via malformed URLs reaching encapsulated not-found handlers","id":"CVE-2026-76169","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":null,"products":[],"type":"auth_bypass","year":"2026"},"n_packages":2,"n_references":2,"next":{"headline":"fast-uri vulnerable to host confusion via percent-encoded scheme normalization","id":"CVE-2026-76172"},"packages":[{"ecosystem":"npm","fixed":["5.12.2"],"introduced":["4.0.0"],"last_affected":[],"package":"fastify","purl":null,"source":"GHSA-p68q-wchp-6fh7"},{"ecosystem":"npm","fixed":["5.12.2"],"introduced":["4.0.0"],"last_affected":[],"package":"fastify","purl":"pkg:npm/fastify","source":"GHSA-p68q-wchp-6fh7"}],"prev":{"headline":"Modcluster-core: mod_cluster advertise listener: unauthenticated dos via crafted multicast datagram","id":"CVE-2026-76166"},"products":["fastify"],"published":"2026-09-04","related":[{"cvss_score":8.1,"headline":"fastify vulnerable to request body replacement via an async validation result collision","id":"CVE-2026-84504","kev_date_added":null,"published":"2026-09-04"},{"cvss_score":7.5,"headline":"fastify vulnerable to header validation bypass via incomplete schema case normalization","id":"CVE-2026-84428","kev_date_added":null,"published":"2026-09-04"},{"cvss_score":7.5,"headline":"fastify vulnerable to request validation bypass via skipped boolean false schemas","id":"CVE-2026-84469","kev_date_added":null,"published":"2026-09-04"},{"cvss_score":7.5,"headline":"fastify vulnerable to Body Schema Validation Bypass via Leading Space in Content-Type Header","id":"CVE-2026-33806","kev_date_added":null,"published":"2026-04-15"},{"cvss_score":7.5,"headline":"Fastify's Content-Type header tab character allows body validation bypass","id":"CVE-2026-25223","kev_date_added":null,"published":"2026-02-03"},{"cvss_score":7.5,"headline":"Fastify vulnerable to invalid content-type parsing, which could lead to validation bypass","id":"CVE-2025-32442","kev_date_added":null,"published":"2025-04-18"}],"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":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-09-04","vendors":["fastify"]},"summary":"An unauthenticated attacker can bypass authentication hooks to read protected responses from encapsulated not-found handlers via malformed URLs.","url":"https://insights.sbomify.com/CVE-2026-76169/"}