High 7.5Published Mar 27, 2026

CVE-2026-34226Happy DOM is a JavaScript implementation of a web browser without its graphical user interface.

Updated under an hour ago (2026-10-19 07:10 UTC)

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It affects capricorn86 happy_dom. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for capricorn86 happy_dom

Exploited in the last 30 days

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Versions prior to 20.8.9 may attach cookies from the current page origin (`window.location`) instead of the request target URL when `fetch(..., { credentials: "include" })` is used. This can leak cookies from origin A to destination B. Version 20.8.9 fixes the issue.

CVSS: 7.5 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness (CWE): CWE-201, CWE-359
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Not given
NVD analysis: Modified
Record last updated: Aug 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

capricorn86 happy_dom capricorn86:happy_dom	before 20.8.9	NVD

References

https://github.com/capricorn86/happy-dom/blob/f8d8cad41e9722fab9eefb9dfb3cca696462e908/packages/happy-dom/src/fetch/utilities/FetchRequestHeaderUtility.tspatch
https://github.com/capricorn86/happy-dom/commit/68324c21d7b98f53f7bb5a7b3e185bda7106e751patch
https://github.com/capricorn86/happy-dom/pull/2117issue-tracking, patch
https://github.com/capricorn86/happy-dom/releases/tag/v20.8.9product, release-notes
https://github.com/capricorn86/happy-dom/security/advisories/GHSA-w4gp-fjgq-3q4gexploit, vendor-advisory
https://access.redhat.com/security/cve/CVE-2026-34226
https://bugzilla.redhat.com/show_bug.cgi?id=2452519
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34226.json

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.