CVE-2026-118660
Happy DOM: SSRF via iframe and link stylesheet when parsing untrusted HTML
CVSS Score
8.6
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-918 |
| Vendor | capricorn86 |
| Product | happy-dom |
| Published | Oct 28, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None
Affected Versions
capricorn86 / happy-dom
< 21.0.0
References
github.com: https://github.com/capricorn86/happy-dom/security/advisories/GHSA-c8p4-j97h-3vg8 github.com: https://github.com/capricorn86/happy-dom/pull/2502 github.com: https://github.com/capricorn86/happy-dom/commit/0a99c7525a1d0043e3182843ae33466ab7b19e74 github.com: https://github.com/capricorn86/happy-dom/releases/tag/v21.0.0