CVE-2026-21710

7.5 HIGH
Published: March 30, 2026 Modified: April 01, 2026
View on NVD

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**

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory

1 reference(s) from NVD

Quick Stats

CVSS v3 Score
7.5 / 10.0
EPSS (Exploit Probability)
0.0%
6th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)