CVE-2026-21717
MEDIUMNode.js 20.x 22.x 24.x 25.x - Denial of Service via V8 String Hash Collision
Title source: llmExploitation Summary
EIP tracks 2 public exploits for CVE-2026-21717. PoCs published by open-flaw, dajneem23.
AI-analyzed exploit summary This repository contains a functional proof-of-concept exploit for CVE-2026-21717, demonstrating a denial-of-service vulnerability in Node.js V8's string hashing mechanism. The PoC crafts a malicious JSON payload with predictable hash collisions, causing severe performance degradation during JSON parsing.
Description
A flaw in V8's string hashing mechanism causes integer-like strings to be hashed to their numeric value, making hash collisions trivially predictable. By crafting a request that causes many such collisions in V8's internal string table, an attacker can significantly degrade performance of the Node.js process. The most common trigger is any endpoint that calls `JSON.parse()` on attacker-controlled input, as JSON parsing automatically internalizes short strings into the affected hash table. This vulnerability affects **20.x, 22.x, 24.x, and 25.x**.
Exploits (2)
This repository contains a functional proof-of-concept exploit for CVE-2026-21717, demonstrating a denial-of-service vulnerability in Node.js V8's string hashing mechanism. The PoC crafts a malicious JSON payload with predictable hash collisions, causing severe performance degradation during JSON parsing.
This repository contains a functional proof-of-concept for CVE-2026-21717, demonstrating a denial-of-service vulnerability in Node.js V8's string hashing mechanism. The PoC exploits predictable hash collisions in integer-like strings to degrade performance during JSON parsing.
References (1)
Scores
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H