CVE-2026-84428

Description

fastify versions before 5.12.2 implement the case-insensitive nature of HTTP header names by lowercasing names in a route's header schema before compiling it, but the transformation is incomplete: it lowercases the properties keys and the root-level required array, and does not lowercase the trigger and dependent names inside the JSON Schema Draft 7 dependencies keyword. Because Node stores request header names in lowercase, a canonical-case dependency such as requiring an authentication header whenever a privileged-mode header is present never matches, and the presence assertion is silently skipped. An unauthenticated remote client can therefore send the header that activates a privileged branch while omitting the header the dependency was meant to require, bypassing the conditional check. Users should upgrade to fastify 5.12.2 or later.

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Produits concernés

• fastify
• Fastify fastify

Scores CVSS

Faiblesses (CWE)

• CWE-178

Références

• https://cna.openjsf.org/security-advisories.html Third Party Advisory
• https://github.com/fastify/fastify/security/advisories/GHSA-9q9j-q6p8-xq58 MitigationVendor Advisory

Ailleurs

• NVD
• CVE.org
• CIRCL Vulnerability-Lookup
• CERT-FR
• GitHub Advisories