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**

Published: 2026-03-30 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Awaiting Analysis，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-21710 is rated High Risk (68.5/100): CVSS High severity, with high exploitation likelihood (EPSS 13.07%, 96th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +13.05% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-21710

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.01% 13.07% +13.05%
2 2026-03-31 — 0.01% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-21710

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2026-21710

OS Trackers for CVE-2026-21710

vendor priority summary link
alpine — CVE-2026-21710: 1 source package rows (nodejs); 4 state rows across 4 repos (3.21-main, 3.22-main, 3.23-main, edge-main); fixed 4, open 0. https://security.alpinelinux.org/vuln/CVE-2026-21710
debian unimportant CVE-2026-21710 unimportant priority: Debian including 1 source packages (nodejs), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2026-21710
redhat high — https://access.redhat.com/security/cve/CVE-2026-21710
suse high CVE-2026-21710 severity important: SUSE including 68 source package names (corepack24-24.14.1-1.1, corepack24-24.14.1-160000.1.1, …), 139 product×package rows across 20 product lines (SUSE Liberty Linux 8, SUSE Liberty Linux 9, … (20 product lines)): Known Not Affected 79, Fixed 55, First Fixed 5. https://www.suse.com/security/cve/CVE-2026-21710/
ubuntu medium CVE-2026-21710 medium priority: Ubuntu including 1 source packages (nodejs), 8 status rows across 8 suites (bionic, focal, jammy, noble, questing, trusty, upstream, xenial): needs-triage 7, released 1. https://ubuntu.com/security/CVE-2026-21710

Affected software / configurations for CVE-2026-21710

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-21710

cvelogic Threat Intelligence