High 8.6Published Oct 28, 2026

CVE-2026-118660Happy DOM: SSRF via iframe and link stylesheet when parsing untrusted HTML

Updated under an hour ago (Oct 30, 2026, 6:10 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Start free and add your stackFree account, 3 products Every CVE for capricorn86 happy-dom Exploited in the last 30 days

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.

CVSS: 8.6 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Weakness (CWE): CWE-918
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Awaiting Analysis
Record last updated: Oct 29, 2026
First seen by InfoSec Signals: Oct 28, 2026

Affected products

Affected products

capricorn86 happy-dom capricorn86:happy_dom (from the name)	before 21.0.0	CNA record

References

References

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

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.