Reliance on Cookies without Validation and Integrity Checking Affecting happy-dom package, versions <20.14.6
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JS-HAPPYDOM-21826828
- published29 Oct 2026
- disclosed28 Oct 2026
- creditRyan Cruz
Introduced: 28 Oct 2026
NewCVE-2026-118661 (opens in a new tab)How to fix?
Upgrade happy-dom to version 20.14.6 or higher.
Overview
happy-dom is a Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. It includes many web standards from WHATWG DOM and HTML.
Affected versions of this package are vulnerable to Reliance on Cookies without Validation and Integrity Checking via the cookie domain scoping logic in CookieDomainUtility and CookieURLUtility, which fails to enforce RFC 6265 domain-match rules and does not consult the Public Suffix List. An attacker-controlled server can set a cookie with a Domain attribute that is not a suffix of the request host (e.g., responding from 127.0.0.1 while claiming Domain=localhost), and happy-dom stores and forwards that cookie to the victim origin. Additionally, CookieURLUtility uses a plain endsWith check without a DNS-label boundary, so a cookie scoped to example.com is incorrectly sent to notexample.com.