CVE-2025-27209

Severity: high (CVSS 7.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-07-18 · updated 2026-06-17
Weakness: CWE-407

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.

Affected products

Node.js: from 24.0.0 before 24.4.1 — fixed in 24.4.1

How to fix

Upgrade to a fixed version: Node.js 24.4.1. Check the vendor advisory for mitigations.

References

https://nodejs.org/en/blog/vulnerability/july-2025-security-releases
http://www.openwall.com/lists/oss-security/2025/07/22/2

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