CVE-2026-21717
Published:March 30, 2026
Updated:May 18, 2026
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.
Affected Packages
https://github.com/nodejs/node.git (GITHUB):
Affected version(s) >=v20.0.0 <v20.20.2Fix Suggestion:
Update to version v20.20.2https://github.com/nodejs/node.git (GITHUB):
Affected version(s) >=v24.0.0 <v24.14.1Fix Suggestion:
Update to version v24.14.1https://github.com/nodejs/node.git (GITHUB):
Affected version(s) >=v22.0.0 <v22.22.2Fix Suggestion:
Update to version v22.22.2https://github.com/nodejs/node.git (GITHUB):
Affected version(s) >=v25.0.0 <v25.8.2Fix Suggestion:
Update to version v25.8.2Additional Notes
The description of this vulnerability differs from MITRE.
Related Resources (1)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.2
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
5.9
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Use of Weak Hash
EPSS
Base Score:
0.03