CVE-2026-21710
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**
| Vendor | nodejs |
| Product | node |
| Ecosystems | |
| Industries | Technology |
| Published | Mar 30, 2026 |
| Last Updated | Mar 31, 2026 |
Get instant alerts for nodejs node
Be the first to know when new high vulnerabilities affecting nodejs node are published — delivered to Slack, Telegram or Discord.
CVSS v3 Breakdown
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H