CVE-2026-21717
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**.
How to fix
Sources list no fixed version or patch link for this vulnerability.
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| nodejs node.js | v ≤ 20.20.1, 22.0.0 ≤ v ≤ 22.22.1, 24.0.0 ≤ v ≤ 24.14.0, 25.0.0 ≤ v ≤ 25.8.1 | — |
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