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.
Weakness
The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Happy_dom | Capricorn86 | * | 20.8.9 (excluding) |
Potential Mitigations
- Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
- Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/12.html
- https://cwe.mitre.org/data/definitions/217.html
- https://cwe.mitre.org/data/definitions/612.html
- https://cwe.mitre.org/data/definitions/613.html
- https://cwe.mitre.org/data/definitions/618.html
- https://cwe.mitre.org/data/definitions/619.html
- https://cwe.mitre.org/data/definitions/621.html
- https://cwe.mitre.org/data/definitions/622.html
- https://cwe.mitre.org/data/definitions/623.html
References
- https://github.com/capricorn86/happy-dom/blob/f8d8cad41e9722fab9eefb9dfb3cca696462e908/packages/happy-dom/src/fetch/utilities/FetchRequestHeaderUtility.ts
- https://github.com/capricorn86/happy-dom/commit/68324c21d7b98f53f7bb5a7b3e185bda7106e751
- https://github.com/capricorn86/happy-dom/pull/2117
- https://github.com/capricorn86/happy-dom/releases/tag/v20.8.9
- https://github.com/capricorn86/happy-dom/security/advisories/GHSA-w4gp-fjgq-3q4g
- https://access.redhat.com/security/cve/CVE-2026-34226
- https://bugzilla.redhat.com/show_bug.cgi?id=2452519
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34226.json