Node.js HTTP Client Desync in Forwarding Proxies CVE-2026-58044
CVE-2026-58044 Published on August 4, 2026
A flaw in Node.js HTTP client can cause a request desynchronization for Node.js-based forwarding proxies that rebuild outbound headers from the visible `IncomingMessage` headers while piping the original body to a reused backend connection. Node.js can omit headers beyond `maxHeadersCount` / `maxHeaderPairs` from `req.headers`, `req.rawHeaders`, and `req.headersDistinct`, while still using those omitted headers internally for HTTP message framing. In particular, `Content-Length` can be hidden from userland while the request body is still delivered. This vulnerability affects all supported release lines: **Node.js 22**, **Node.js 24**, and **Node.js 26**.
Weakness Type
What is a HTTP Request Smuggling Vulnerability?
When malformed or abnormal HTTP requests are interpreted by one or more entities in the data flow between the user and the web server, such as a proxy or firewall, they can be interpreted inconsistently, allowing the attacker to "smuggle" a request to one device without the other device being aware of it.
CVE-2026-58044 has been classified to as a HTTP Request Smuggling vulnerability or weakness.
Affected Versions
nodejs node:- Version 26.5.0, <= 26.5.0 is affected.
- Version 24.18.0, <= 24.18.0 is affected.
- Version 22.23.1, <= 22.23.1 is affected.