CVE-2023-51701: fastify fastify-reply-from HTTP Request/Response Smuggling

Vulnerability summary

CVE-2023-51701 is a high (CVSS 7.5) HTTP Request/Response Smuggling vulnerability in fastify fastify-reply-from. EPSS estimates a 0.48% chance of exploitation in the next 30 days, higher than 40% of scored vulnerabilities.

Timeline

1. 08-01-2024
   PublishedVulnerability first disclosed.
2. 03-06-2025
   Last modifiedVulnerability information updated.

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.

• CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.