AUGUST 4, 2026
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Case File

CVE-2026-21710

HIGH · CVSS 7.5 EPSS 26.36%

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2026-03-30 · Last synced 2026-08-04

CyberRota Analysis

This is a high severity vulnerability with a CVSS score of 7.5. Its EPSS score suggests a 26.4% probability of exploitation in the next 30 days.

CVE
CVE-2026-21710
Severity
HIGH
CVSS
7.5
EPSS
26.36%

Original 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**