CVE-2026-21710

high · 7.5

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**

7.5

CVSS

25.0%

EPSS (exploit prob.)

98th

EPSS percentile

2026-03-30

Published

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weaknesses

CWE-770CWE-843

Affected products

Vendor	Product	Affected versions
nodejs	node.js	<= 20.20.1
nodejs	node.js	>= 22.0.0, <= 22.22.1
nodejs	node.js	>= 24.0.0, <= 24.14.0
nodejs	node.js	>= 25.0.0, <= 25.8.1
redhat	enterprise_linux	8.0
redhat	enterprise_linux	9.0
redhat	enterprise_linux	10.0
redhat	enterprise_linux_eus	9.4
redhat	enterprise_linux_eus	9.6
redhat	enterprise_linux_eus	10.0

Check a specific version with /api/v1/cve/match.

References

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-21710