Is CVE-2026-21710 being actively exploited?

CVE-2026-21710 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

What is the CVSS score for CVE-2026-21710?

CVE-2026-21710 has a CVSS 3.1 base score of 7.5 (HIGH).

CVE-2026-21710

HIGH · CVSS 7.5EPSS 25.0%EU EUVD

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**

Key facts

CVSS score: 7.5 (v3.1)
Severity: HIGH
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-770
EPSS score: 25.0% (98th percentile)
In CISA KEV: No
In EU EUVD: Yes (EUVD-2026-17170)
Published: March 30, 2026
NVD last modified: August 19, 2026
Status: Analyzed

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2026-17170 in the EU Vulnerability Database. Last updated in EUVD on July 15, 2026.

View on the EU Vulnerability Database

Affected products

nodejs / node.js
redhat / enterprise linux
redhat / enterprise linux
redhat / enterprise linux
redhat / enterprise linux eus
redhat / enterprise linux eus
redhat / enterprise linux eus

Certified products that may be affected

32 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.

Red Hat Enterprise Linux 8 NSS Cryptographic Module - Red Hat, Inc. - FIPS 140 5513 - active
Red Hat Enterprise Linux 8 Kernel Cryptographic API - Red Hat, LLC - FIPS 140 5461 - active
Red Hat Enterprise Linux 9 Kernel Cryptographic API - Red Hat, Inc. - FIPS 140 5445 - active
Red Hat Enterprise Linux 9 libgcrypt - Red Hat, Inc. - FIPS 140 5366 - active
Red Hat Enterprise Linux 8 Kernel Cryptographic API - Red Hat, Inc. - FIPS 140 5089 - active

See all 32 in the Security Certifications Explorer.

References

https://access.redhat.com/errata/RHSA-2026:7080(Third Party Advisory)
https://access.redhat.com/errata/RHSA-2026:7123(Third Party Advisory)
https://access.redhat.com/errata/RHSA-2026:7302(Third Party Advisory)
https://access.redhat.com/errata/RHSA-2026:7310(Third Party Advisory)
https://access.redhat.com/errata/RHSA-2026:7350(Third Party Advisory)
https://access.redhat.com/errata/RHSA-2026:7670(Third Party Advisory)
https://access.redhat.com/errata/RHSA-2026:7675(Third Party Advisory)
https://access.redhat.com/errata/RHSA-2026:7896(Third Party Advisory)
https://access.redhat.com/errata/RHSA-2026:7983(Third Party Advisory)
https://access.redhat.com/errata/RHSA-2026:8339(Third Party Advisory)
https://access.redhat.com/errata/RHSA-2026:9711(Third Party Advisory)
https://access.redhat.com/errata/RHSA-2026:9874(Third Party Advisory)
https://access.redhat.com/security/cve/CVE-2026-21710(Third Party Advisory)
https://bugzilla.redhat.com/show_bug.cgi?id=2453151(Issue Tracking)
https://nodejs.org/en/blog/vulnerability/march-2026-security-releases(Vendor Advisory)
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-21710.json(Third Party Advisory)

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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