CVE-2026-21717
MEDIUM 5.9EPSS 0.3%
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**.
- CVSS v3.1
- 5.9 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS v3.0
- 5.9 MEDIUM
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS
- 0.27% chance of exploitation in the next 30 days, 19th percentile
- Published
- 2026-03-30
- Updated
- 2026-05-10
Proof-of-concept exploits (1)
- open-flaw/CVE-2026-217170★ · 2026-04-07