Improper error handling in Node.js - CVE-2026-21710
Published: March 25, 2026
Vulnerability identifier: #VU124542
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-21710
CWE-ID: CWE-388
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Node.js Foundation
Affected software:
Node.js
Node.js
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper handling of special property names in HTTP headers in req.headersDistinct when parsing incoming HTTP requests. A remote attacker can send a request with a header named __proto__ to trigger a TypeError when the application accesses req.headersDistinct, crashing the Node.js process.
The exception occurs synchronously in a property getter and cannot be caught without wrapping every access in try/catch.
How to mitigate CVE-2026-21710
Install security update from vendor's website.