Vulnerability in Capricorn86 Happy-dom
CVE-2026-34226
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(…
EPSS: 0.001 (17.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
Affected products
- Capricorn86 Happy-dom — versions < 20.8.9
Weakness classification (CWE)
References
- https://github.com/capricorn86/happy-dom/security/advisories/GHSA-w4gp-fjgq-3q4g (x_refsource_CONFIRM)
- https://github.com/capricorn86/happy-dom/pull/2117 (x_refsource_MISC)
- https://github.com/capricorn86/happy-dom/commit/68324c21d7b98f53f7bb5a7b3e185bda7106e751 (x_refsource_MISC)
- https://github.com/capricorn86/happy-dom/blob/f8d8cad41e9722fab9eefb9dfb3cca696462e908/packages/happy-dom/src/fetch/utilities/FetchRequestHeaderUtility.ts (x_refsource_MISC)
- https://github.com/capricorn86/happy-dom/releases/tag/v20.8.9 (x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-34226?
- CVE-2026-34226 is a high-severity vulnerability in Capricorn86 Happy-dom, classified under Insertion of Sensitive Information into Sent Data. CVSS score: 7.5/10. Published 2026-03-27.
- How severe is CVE-2026-34226?
- High severity. CVSS v3 base score is 7.5 out of 10.