CVE-2026-118660 Happy DOM: SSRF via iframe and link stylesheet when parsing untrusted HTML
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-118660?
CVE-2026-118660 is a high-severity vulnerability in capricorn86 happy-dom, published on 28 Oct 2026.
Official description
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.
Weakness: CWE-918
Which versions are affected by CVE-2026-118660?
2 open source packages ship an affected version, including happy-dom.
| Package | Affected | Fixed in |
|---|---|---|
happy-dom npm | All versions | 21.0.0 |
happy-dom npm | All versions | 21.0.0 |
How do I fix CVE-2026-118660?
Upgrade happy-dom to 21.0.0 or later.
Is CVE-2026-118660 being exploited?
There is no known exploitation of CVE-2026-118660 in the wild and no public exploit code.
Sources
Also known as GHSA-c8p4-j97h-3vg8.