CVE-2026-34226 HIGH

CVE-2026-34226: Happy DOM's fetch credentials include uses page-origin cookies instead of target-origin cookies

Vendor Capricorn86
Product happy-dom
Weakness CWE-201
Published March 27, 2026
Last update June 30, 2026
View on NVD All CVEs

CVSS base score

7.5/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality High
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

March 27, 2026 CVE published
June 30, 2026 Record updated