Prototype pollution in Express - CVE-2024-51999
Published: December 1, 2025
Vulnerability identifier: #VU118878
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2024-51999
CWE-ID: CWE-1321
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Express.js
Affected software:
Express
Express
Detailed vulnerability description
The vulnerability allows a remote attacker to execute arbitrary JavaScript code.
The vulnerability exists due to improper input validation when using the extended query parser in express ('query parser': 'extended'). A remote attacker can pass specially crafted input to the application and perform prototype pollution, which can result in information disclosure or data manipulation.
How to mitigate CVE-2024-51999
Install updates from vendor's website.