CVE-2026-21710

CVE Details

Release Date:	2026-03-30
Impact:	Important	What is this?

Description

A flaw in Node.js HTTP request handling causes an uncaught `TypeError` when a request is received with a header named `__proto__` and the application accesses `req.headersDistinct`. When this occurs, `dest["__proto__"]` resolves to `Object.prototype` rather than `undefined`, causing `.push()` to be called on a non-array. This exception is thrown synchronously inside a property getter and cannot be intercepted by `error` event listeners, meaning it cannot be handled without wrapping every `req.headersDistinct` access in a `try/catch`. * This vulnerability affects all Node.js HTTP servers on **20.x, 22.x, 24.x, and v25.x**

See more information about CVE-2026-21710 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	7.5
Vector String:	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Version:	3.1
Attack Vector:	Network
Attack Complexity:	Low
Privileges Required:	None
User Interaction:	None
Scope:	Unchanged
Confidentiality Impact:	None
Integrity Impact:	None
Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 10 (nodejs22)	ELSA-2026-7080	2026-04-08
Oracle Linux version 8 (nodejs)	ELSA-2026-7123	2026-04-09
Oracle Linux version 8 (nodejs-nodemon)	ELSA-2026-7123	2026-04-09
Oracle Linux version 8 (nodejs-packaging)	ELSA-2026-7123	2026-04-09
Oracle Linux version 9 (nodejs)	ELSA-2026-7302	2026-04-10
Oracle Linux version 9 (nodejs)	ELSA-2026-7350	2026-04-10
Oracle Linux version 9 (nodejs-nodemon)	ELSA-2026-7302	2026-04-10
Oracle Linux version 9 (nodejs-nodemon)	ELSA-2026-7350	2026-04-10
Oracle Linux version 9 (nodejs-packaging)	ELSA-2026-7302	2026-04-10
Oracle Linux version 9 (nodejs-packaging)	ELSA-2026-7350	2026-04-10