{"id":"CVE-2026-84469","sourceIdentifier":"ce714d77-add3-4f53-aff5-83d477b104bb","published":"2026-09-04T10:17:13.677","lastModified":"2026-09-15T20:06:50.543","vulnStatus":"Analyzed","cveTags":[],"descriptions":[{"lang":"en","value":"fastify versions before 5.12.2 decide whether to compile a request schema based on JavaScript truthiness, but JSON Schema Draft 7 defines the boolean false as a valid schema that rejects every instance. When an application assigns false to a route's body, querystring, params, or headers schema to deny all input, fastify treats it as a missing schema, compiles no validator, and runs the route handler on any request. An unauthenticated remote client can therefore reach a handler that a valid deny-all schema was intended to make unreachable, a complete validation bypass that can lead to unauthorized state changes or execution of disabled operations. Users should upgrade to fastify 5.12.2 or later."}],"affected":[{"source":"ce714d77-add3-4f53-aff5-83d477b104bb","affectedData":[{"vendor":"fastify","product":"fastify","defaultStatus":"unaffected","packageURL":"pkg:npm/fastify","versions":[{"version":"0","lessThan":"5.12.2","versionType":"semver","status":"affected"},{"version":"5.12.2","versionType":"semver","status":"unaffected"}]}]}],"metrics":{"cvssMetricV31":[{"source":"ce714d77-add3-4f53-aff5-83d477b104bb","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"HIGH","availabilityImpact":"NONE"},"exploitabilityScore":3.9,"impactScore":3.6}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-09-04T19:34:03.487072Z","id":"CVE-2026-84469","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"weaknesses":[{"source":"ce714d77-add3-4f53-aff5-83d477b104bb","type":"Secondary","description":[{"lang":"en","value":"CWE-20"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:fastify:fastify:*:*:*:*:*:node.js:*:*","versionEndExcluding":"5.12.2","matchCriteriaId":"44437B15-E71B-4EDB-A998-E6A82C402616"}]}]}],"references":[{"url":"https://cna.openjsf.org/security-advisories.html","source":"ce714d77-add3-4f53-aff5-83d477b104bb","tags":["Third Party Advisory"]},{"url":"https://github.com/fastify/fastify/security/advisories/GHSA-hwr6-493r-vm6h","source":"ce714d77-add3-4f53-aff5-83d477b104bb","tags":["Mitigation","Vendor Advisory"]}]}