Answer in brief
CVE-2026-118660 records a High severity (CVSS 8.6) vulnerability in Happy DOM: SSRF via iframe and link stylesheet when parsing untrusted HTML. The current sources do not mark it as known exploited. The current feed maps capricorn86/happy-dom (generic), happy-dom (npm). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.6. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps capricorn86/happy-dom (generic), happy-dom (npm). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| capricorn86/happy-domgeneric | <21.0.0 | 21.0.0 |
| happy-domnpm | <=20.14.6 | 21.0.0 |
Published upstream
Oct 28, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 28, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 28, 2026
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.
Quoted source text, attributed separately from HOL analysis.