CVE-2026-34226

HIGH7.5/ 10.0
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Published: March 27, 2026 at 10:16 PM
Modified: April 1, 2026 at 01:26 PM
Source: security-advisories@github.com

Vulnerability Description

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 Metrics

Base Score
7.5
Severity
HIGH
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Weaknesses (CWE)

CWE-201
CWE-359
Source: security-advisories@github.com

References & Intelligence

https://github.com/capricorn86/happy-dom/blob/f8d8cad41e9722fab9eefb9dfb3cca696462e908/packages/happy-dom/src/fetch/utilities/FetchRequestHeaderUtility.ts
Source: security-advisories@github.com
Patch
https://github.com/capricorn86/happy-dom/commit/68324c21d7b98f53f7bb5a7b3e185bda7106e751
Source: security-advisories@github.com
Patch
https://github.com/capricorn86/happy-dom/pull/2117
Source: security-advisories@github.com
Issue TrackingPatch
https://github.com/capricorn86/happy-dom/releases/tag/v20.8.9
Source: security-advisories@github.com
ProductRelease Notes
https://github.com/capricorn86/happy-dom/security/advisories/GHSA-w4gp-fjgq-3q4g
Source: security-advisories@github.com
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