CVE-2026-118660

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Prior to 21.0.0, Happy DOM loads iframe src URLs and link rel="stylesheet" href URLs by default while parsing untrusted HTML on the server because disableIframePageLoading and disableCSSFileLoading default to false. An attacker who controls parsed HTML can therefore cause server-side requests to arbitrary internal or cloud endpoints without an application opt-in and may expose confidential responses or credentials returned by those endpoints. This issue is fixed in version 21.0.0.

Score

CVSS 3.1 8.6 High

Status

Received - security-advisories@github.com

Published

2026-10-28

Last modified

2026-10-28

Weaknesses

CWE-918

Affected products

• Happy-dom (Capricorn86)

References

• https://github.com/capricorn86/happy-dom/security/advisories/GHSA-c8p4-j97h-3vg8
• https://github.com/capricorn86/happy-dom/pull/2502
• https://github.com/capricorn86/happy-dom/commit/0a99c7525a1d0043e3182843ae33466ab7b19e74
• https://github.com/capricorn86/happy-dom/releases/tag/v21.0.0