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
CVE-2026-21710
HIGHPre-NVD 7.57.5—Elevated
EchelonGraph scoreMEDIUM confidence
Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-03-30. the CNA's CVSS baseline 7.5; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: cna:github_m, ghsa
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 26%CVSS: 7.5Exploit: NoneExposed: 0
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EPSS
- 97.8%
- KEV
- Not listed
Published
March 30, 2026
Last Modified
June 30, 2026
Advisory Details (10)
Auto-updated Jul 3, 2026Patch available. Sources: redhat.
redhat Patch Available
Affected: Red Hat Enterprise Linux 9.6 Extended Update Support.
https://access.redhat.com/errata/RHSA-2026:7983redhat Patch Available
Affected: Red Hat Enterprise Linux 9.
https://access.redhat.com/errata/RHSA-2026:7896redhat Patch Available
Affected: Red Hat Enterprise Linux 10.
https://access.redhat.com/errata/RHSA-2026:7675redhat Patch Available
Affected: Red Hat Enterprise Linux 8.
https://access.redhat.com/errata/RHSA-2026:7670redhat Patch Available
Affected: Red Hat Enterprise Linux 9.
https://access.redhat.com/errata/RHSA-2026:7350redhat Patch Available
Affected: Red Hat Enterprise Linux 10.0 Extended Update Support.
https://access.redhat.com/errata/RHSA-2026:7310redhat Patch Available
Affected: Red Hat Enterprise Linux 9.
https://access.redhat.com/errata/RHSA-2026:7302redhat Patch Available
Affected: Red Hat Enterprise Linux 8.
https://access.redhat.com/errata/RHSA-2026:7123redhat Patch Available
Affected: Red Hat Enterprise Linux 10.
https://access.redhat.com/errata/RHSA-2026:7080generic
Node.js — Tuesday, March 24, 2026 Security Releases
https://nodejs.org/en/blog/vulnerability/march-2026-security-releasesVendor Advisories for CVE-2026-21710(14)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- CVE-2026-21710Microsoft Security Response Center (MSRC)High
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**
- RHSA-2026:9874Red Hat Product SecurityHigh
Red Hat Security Advisory: nodejs:20 security update
- RHSA-2026:9711Red Hat Product SecurityHigh
Red Hat Security Advisory: nodejs:20 security update
- RHSA-2026:8339Red Hat Product SecurityHigh
Red Hat Security Advisory: nodejs:20 security update
- RHSA-2026:7983Red Hat Product SecurityHigh
Red Hat Security Advisory: nodejs:22 security update
- RHSA-2026:7896Red Hat Product SecurityHigh
Red Hat Security Advisory: nodejs:20 security update
- RHSA-2026:7670Red Hat Product SecurityHigh
Red Hat Security Advisory: nodejs:24 security update
- RHSA-2026:7675Red Hat Product SecurityHigh
Red Hat Security Advisory: nodejs24 security update
- +6 more
Patch Availability(12)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| redhat | nodejs:20-9040020260421133644.rhel9 | 2026-04-22 | redhat |
| redhat | nodejs:20-9060020260422064119.rhel9 | 2026-04-22 | redhat |
| redhat | nodejs:20-8100020260414073138.489197e6 | 2026-04-15 | redhat |
| redhat | nodejs:22-9060020260409121057.rhel9 | 2026-04-14 | redhat |
| redhat | nodejs24-1:24.14.1-2.el10_1 | 2026-04-13 | redhat |
| redhat | nodejs:20-9070020260409073121.rhel9 | 2026-04-13 | redhat |
| redhat | nodejs:24-8100020260408131901.6d880403 | 2026-04-13 | redhat |
| redhat | nodejs:22-9070020260401095228.rhel9 | 2026-04-09 | redhat |
| redhat | nodejs22-1:22.22.2-2.el10_0 | 2026-04-09 | redhat |
| redhat | nodejs:24-9070020260402152654.rhel9 | 2026-04-09 | redhat |
| redhat | nodejs22-1:22.22.2-1.el10_1 | 2026-04-08 | redhat |
| redhat | nodejs:22-8100020260331102257.6d880403 | 2026-04-08 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 8× in last 7d / 17× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-12 05:46 UTCEPSS rescore
- 2026-07-12 05:46 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-08 15:15 UTCEPSS rescore
- 2026-07-08 15:15 UTCEPSS rescore
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-01 15:06 UTCEPSS rescore
- 2026-07-01 15:06 UTCEPSS rescore
- 2026-06-30 23:22 UTCEPSS rescore
- 2026-06-30 04:30 UTCEG score recompute
- 2026-06-30 04:30 UTCVendor advisory
- 2026-06-30 04:30 UTCGHSA enrichment
Related CVEs(same vendor + same CWE)
Same vendor
10 shownmsrc · redhat
Same CWE
10 shownCWE-843
- CVE-2016-1000005EG 9.8CRITICAL
- CVE-2012-0507EG 9.8 KEVEPSS 100%CRITICAL
- CVE-2017-5070NVD 8.8EG 9.0 KEVEPSS 98%HIGH
- CVE-2017-11292NVD 8.8EG 9.0 KEVEPSS 96%HIGH
- CVE-2017-8291NVD 7.8EG 9.0 KEVEPSS 100%HIGH
- CVE-2017-0037NVD 8.1EG 9.0 KEVEPSS 100%HIGH
- CVE-2011-0611NVD 8.8EG 9.0 KEVEPSS 100%HIGH
- CVE-2012-4512EG 8.8EPSS 96%HIGH
- CVE-2018-14286EG 8.8HIGH
- CVE-2018-14285EG 8.8HIGH
Frequently asked(5)
What is CVE-2026-21710?
CVE-2026-21710 is a high vulnerability published on March 30, 2026. 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…
When was CVE-2026-21710 disclosed?
CVE-2026-21710 was first published in the National Vulnerability Database on March 30, 2026, with the most recent update on June 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-21710 actively exploited?
CVE-2026-21710 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 97.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-21710?
CVE-2026-21710 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-21710?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-21710, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-21710
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