CVE-2026-34226: CWE-201: Insertion of Sensitive Information Into Sent Data in capricorn86 happy-dom
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.
AI Analysis
Technical Summary
CVE-2026-34226 is a vulnerability in Happy DOM, a JavaScript implementation of a web browser without a GUI. In versions before 20.8.9, when fetch is called with credentials set to "include", cookies from the current page origin (window.location) may be incorrectly attached to requests sent to a different target URL. This behavior can cause sensitive cookie information to leak from origin A to origin B. The vulnerability is classified under CWE-201 (Insertion of Sensitive Information Into Sent Data) and CWE-359. The issue is resolved in Happy DOM version 20.8.9.
Potential Impact
The vulnerability allows leakage of sensitive cookie information across origins, potentially exposing user session data or other sensitive cookies to unintended destinations. This can compromise confidentiality but does not affect integrity or availability. The CVSS v3.1 score is 7.5 (High), reflecting network attack vector, low attack complexity, no privileges required, no user interaction, and high confidentiality impact.
Mitigation Recommendations
An official fix is available in Happy DOM version 20.8.9. Users and organizations should upgrade to version 20.8.9 or later to remediate this vulnerability. No additional mitigations are indicated by the vendor advisory.
CVE-2026-34226: CWE-201: Insertion of Sensitive Information Into Sent Data in capricorn86 happy-dom
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 v3.1
Score 7.5high
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-34226 is a vulnerability in Happy DOM, a JavaScript implementation of a web browser without a GUI. In versions before 20.8.9, when fetch is called with credentials set to "include", cookies from the current page origin (window.location) may be incorrectly attached to requests sent to a different target URL. This behavior can cause sensitive cookie information to leak from origin A to origin B. The vulnerability is classified under CWE-201 (Insertion of Sensitive Information Into Sent Data) and CWE-359. The issue is resolved in Happy DOM version 20.8.9.
Potential Impact
The vulnerability allows leakage of sensitive cookie information across origins, potentially exposing user session data or other sensitive cookies to unintended destinations. This can compromise confidentiality but does not affect integrity or availability. The CVSS v3.1 score is 7.5 (High), reflecting network attack vector, low attack complexity, no privileges required, no user interaction, and high confidentiality impact.
Mitigation Recommendations
An official fix is available in Happy DOM version 20.8.9. Users and organizations should upgrade to version 20.8.9 or later to remediate this vulnerability. No additional mitigations are indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-03-26T16:22:29.033Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2026-34226","vendor":"Red Hat"}]
Threat ID: 69c6f6ca3c064ed76ff81bc0
Added to database: 03/27/2026, 21:29:46 UTC
Last enriched: 07/15/2026, 09:01:53 UTC
Last updated: 07/31/2026, 19:22:58 UTC
Views: 136
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