CVE-2026-21717
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**.
- Score
- CVSS 3.1 5.9 Medium
- Status
- Analyzed - support@hackerone.com
- Published
- 2026-03-30
- Last modified
- 2026-05-10
- Weaknesses
- CWE-328
Affected products
References
- https://nodejs.org/en/blog/vulnerability/march-2026-security-releases
