Insertion of Sensitive Information Into Sent Data Affecting happy-dom package, versions <20.8.9
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-15810980
- published29 Mar 2026
- disclosed27 Mar 2026
- creditr74tech
Introduced: 27 Mar 2026
NewCVE-2026-34226 (opens in a new tab)How to fix?
Upgrade happy-dom to version 20.8.9 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 Insertion of Sensitive Information Into Sent Data via the fetch requests when using the credentials: "include" option. An attacker can obtain cookies belonging to the page origin by initiating requests to a different target origin, potentially leading to unauthorized access to sensitive information.