CVE-2026-21710
HIGHNode.js 20.x 22.x 24.x 25.x - Denial of Service via __proto__ Header Handling
Title source: llmExploitation Summary
EIP tracks 2 public exploits for CVE-2026-21710. PoCs published by open-flaw, dajneem23.
AI-analyzed exploit summary This repository contains a functional proof-of-concept exploit for CVE-2026-21710, a DoS vulnerability in Node.js caused by prototype pollution in the `req.headersDistinct` getter. The PoC demonstrates the crash by sending a crafted HTTP request with a `__proto__` header.
Description
A flaw in Node.js HTTP request handling causes an uncaught `TypeError` when a request is received with a header named `__proto__` and the application accesses `req.headersDistinct`. When this occurs, `dest["__proto__"]` resolves to `Object.prototype` rather than `undefined`, causing `.push()` to be called on a non-array. This exception is thrown synchronously inside a property getter and cannot be intercepted by `error` event listeners, meaning it cannot be handled without wrapping every `req.headersDistinct` access in a `try/catch`. * This vulnerability affects all Node.js HTTP servers on **20.x, 22.x, 24.x, and v25.x**
Exploits (2)
This repository contains a functional proof-of-concept exploit for CVE-2026-21710, a DoS vulnerability in Node.js caused by prototype pollution in the `req.headersDistinct` getter. The PoC demonstrates the crash by sending a crafted HTTP request with a `__proto__` header.
This repository contains a functional proof-of-concept exploit for CVE-2026-21710, a DoS vulnerability in Node.js caused by prototype pollution in the `req.headersDistinct` getter. The exploit sends a crafted HTTP request with a `__proto__` header, triggering an uncaught `TypeError` that crashes the Node.js process.
References (1)
Scores
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H