What’s Vulnerable › Vulnerabilities

CVE-2023-51701: @fastify-reply-from JSON Content-Type parsing confusion

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2024-01-08 · updated 2026-06-17
• Weakness: CWE-444

Description

fastify-reply-from is a Fastify plugin to forward the current HTTP request to another server. A reverse proxy server built with `@fastify/reply-from` could misinterpret the incoming body by passing an header `ContentType: application/json ; charset=utf-8`. This can lead to bypass of security checks. This vulnerability has been patched in '@fastify/reply-from` version 9.6.0.

Affected products

• fastify-reply-from: before 9.6.0 — fixed in 9.6.0

How to fix

Upgrade to a fixed version: fastify-reply-from 9.6.0. Check the vendor advisory for mitigations.

References

• https://github.com/fastify/fastify-reply-from/releases/tag/v9.6.0
• https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-v2v2-hph8-q5xp
• https://github.com/fastify/fastify-reply-from/releases/tag/v9.6.0
• https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-v2v2-hph8-q5xp

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