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CVE-2026-34226

HIGHCVSS 7.5/10EPSS 0.46%

Last modified

CVE-2026-34226 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.46% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS Probability
0.46%

36.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
Capricorn86Happy Dom< 20.8.9

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2026-34226?
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.
How severe is CVE-2026-34226?
CVE-2026-34226 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.46% probability of exploitation in the next 30 days.
How do I fix CVE-2026-34226?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST