SSRF in Capricorn86 Happy-Dom

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.

Vulnerability class: SSRF (Server-Side Request Forgery)

Published .

CVSS v3 metric

CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-118660?
CVE-2026-118660 is a high-severity vulnerability in Capricorn86 Happy-Dom, classified under Server-Side Request Forgery (SSRF). CVSS score: 8.6/10. Published 2026-10-28.
How severe is CVE-2026-118660?
High severity. CVSS v3 base score is 8.6 out of 10.