# CVE-2025-27209: Node.js: Inefficient Algorithmic Complexity

CVE-2025-27209 is fixed in Node.js on 1 platform by Node.js 24.4.1 (version 24.4.1), released July 15, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-27209
- Priority: High
- CVSS: 7.5
- EPSS: 0.0125
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 18, 2025
- Weakness: CWE-407: Inefficient Algorithmic Complexity
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2025-27209

## Description

The V8 release used in Node.js v24.0.0 has changed how string hashes are computed using rapidhash. This implementation re-introduces the HashDoS vulnerability as an attacker who can control the strings to be hashed can generate many hash collisions - an attacker can generate collisions even without knowing the hash-seed.    * This vulnerability affects Node.js v24.x users.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Windows apps | Node.js | 24.4.1 | [Node.js 24.4.1](https://patchblox.com/security/data/fix/windows-app/openjs.nodejs-24.4.1.md) | Jul 15, 2025 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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