CVE-2026-21710 in Node.js 22.16.0

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

Severity

High 7.5

Exploitation

25% chance of exploit
in the next 30 days

Fix

No fixed version listed yet

Where

App / API

How it matched

Exact version match

First seen

2026-11-05 01:13:58 UTC

Source

https://nvd.nist.gov/vuln/detail/CVE-2026-21710