CVE-2026-21717

nodejs: v8: Node.js: Denial of Service via V8 string hashing mechanism due to predictable hash collisions

Published Mar 30, 2026 CVSS 3.1 · 5.9 Medium EPSS < 1% KEV · Not listed
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**.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DSA Debian DSA DSA-6183-1 nodejs security update
History
Type Values Removed Values Added
First Time appeared Nodejs node.js
CPEs cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*
Vendors & Products Nodejs node.js
Type Values Removed Values Added
Weaknesses CWE-770
Type Values Removed Values Added
Title nodejs: v8: Node.js: Denial of Service via V8 string hashing mechanism due to predictable hash collisions
First Time appeared Nodejs
Nodejs nodejs
Weaknesses CWE-328
CWE-770
Vendors & Products Nodejs
Nodejs nodejs
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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
Metrics cvssV3_0

{'score': 5.9, 'vector': 'CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
hackerone
Published
Updated
May 10, 2026, 1:16 PM
Reserved
Jan 4, 2026, 3:00 PM
Status
Analyzed
Published
Mar 30, 2026, 8:16 PM
Modified
Aug 19, 2026, 12:54 PM
Severity
Moderate
Public date
Mar 30, 2026, 7:07 PM