fastify vulnerable to Body Schema Validation Bypass via Leading Space in Content-Type Header
Impact: Fastify applications using schema.body.content for per-content-type body validation can have validation bypassed entirely by prepending a space to the Content-Type header. The body is still parsed correctly but schema validation is skipped. This is a regression introduced in fastify >= 5.3.2 by the fix for CVE-2025-32442 Patches: Upgrade to fastify v5.8.5 or later. Workarounds: None. Upgrade to the patched version.
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describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2025-32442US | — | — | ||
Fastify is a fast and low overhead web framework, for Node.js. In versions 5.0.0 to 5.3.0 as well as version 4.29.0, applications that specify different validation strategies for d… | ||||
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references
External citations — patches, advisories, analysis.
- https://access.redhat.com/security/cve/CVE-2026-33806ADVISORY
- https://bugzilla.redhat.com/show_bug.cgi?id=2458596REPORT
- https://cna.openjsf.org/security-advisories.htmlADVISORY
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33806.jsonADVISORY
- https://github.com/fastify/fastify/security/advisories/GHSA-mg2h-6x62-wpwcADVISORY
- https://nvd.nist.gov/vuln/detail/CVE-2026-33806ADVISORY
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33806.jsonWEB
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