CVE-2026-84469
Dashboard / Vulnerabilities / CVE-2026-84469
Summary: fastify vulnerable to request validation bypass via skipped boolean false schemas
Details: 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.
References: https://cna.openjsf.org/security-advisories.html, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/84xxx/CVE-2026-84469.json, https://github.com/fastify/fastify/security/advisories/GHSA-hwr6-493r-vm6h, https://nvd.nist.gov/vuln/detail/CVE-2026-84469
Affected packages
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