CVE-2026-21710 — Allocation of Resources Without Limits or Throttling in Node
Severity
7.5HIGHNVD
EPSS
0.0%
top 94.25%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
Timeline
PublishedMar 30
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.h…
CVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitability: 3.9 | Impact: 3.6
Affected Packages3 packages
🔴Vulnerability Details
4📋Vendor Advisories
2🕵️Threat Intelligence
1💬Community
1Bugzilla▶
CVE-2026-21710 Node.js: Node.js: Denial of Service due to crafted HTTP `__proto__` header↗2026-03-30