CVE-2026-21710A 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`.
Updated under an hour ago ()
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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**
CVSS
7.5 HIGH (v3.0, CNA)CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
from 20.20.1 through 20.20.1; from 22.22.1 through 22.22.1; from 24.14.0 through 24.14.0; from 25.8.1 through 25.8.1; from 4.0 before 4.*; from 5.0 before 5.*; from 6.0 before 6.*; from 7.0 before 7.*; and 12 more ranges
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.
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