JavaScript Vulnerability in Happy DOM Affects Cookie Handling
CVE-2026-34226

7.5HIGH

Key Information:

Vendor

Capricorn86

Status
Happy-dom
Vendor
CVE Published:
27 March 2026

What is CVE-2026-34226?

Happy DOM, a JavaScript implementation of a web browser, has a vulnerability that allows it to attach cookies from the current page origin instead of the intended request target URL when using the fetch function with credentials included. This can lead to potential exposure of cookies between different origins, posing a significant risk to user privacy and data integrity. The issue has been addressed in version 20.8.9. For more information, please refer to the provided references.

Affected Version(s)

happy-dom < 20.8.9

References

https://github.com/capricorn86/happy-dom/security/advisor...
x_refsource_CONFIRM
https://github.com/capricorn86/happy-dom/pull/2117
x_refsource_MISC
https://github.com/capricorn86/happy-dom/commit/68324c21d...
x_refsource_MISC

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
High
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.