{"cve":"CVE-2026-21710","nvd":{"published":"2026-03-30T20:16:18.210","modified":"2026-08-19T14:32:04.833","status":"Analyzed","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`.\r\n\r\nWhen 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`.\r\n\r\n* This vulnerability affects all Node.js HTTP servers on **20.x, 22.x, 24.x, and v25.x**","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-770","CWE-843"],"references":["https://nodejs.org/en/blog/vulnerability/march-2026-security-releases","https://access.redhat.com/errata/RHSA-2026:7080","https://access.redhat.com/errata/RHSA-2026:7123","https://access.redhat.com/errata/RHSA-2026:7302","https://access.redhat.com/errata/RHSA-2026:7310"],"products":["nodejs:node.js","redhat:enterprise_linux","redhat:enterprise_linux_eus"],"source":"nvd","synced_at":"2026-10-19T22:28:18.033120106+00:00"},"epss":{"cve":"CVE-2026-21710","score":0.25443,"percentile":0.9795,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}