CVE-2026-21717

medium

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**.

References

https://nodejs.org/en/blog/vulnerability/march-2026-security-releases

Details

Source: Mitre, NVD

Published: 2026-03-30

Updated: 2026-04-01

Risk Information

CVSS v2

Base Score: 5.5

Vector: CVSS2#AV:L/AC:H/Au:S/C:C/I:C/A:N

Severity: Medium

CVSS v3

Base Score: 5.9

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Severity: Medium

EPSS

EPSS: 0.00017