CVE-2026-118659

HIGH 7.5

@happy-dom/server-renderer: ServerRendererServer Target-Origin Bypass SSRF / Open Proxy

CVSS Score

7.5

EPSS Score

0.0%

EPSS Percentile

0th

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Prior to 21.0.2, the Happy DOM server-renderer package's ServerRendererServer accepts unauthenticated HTTP/2 requests and resolves attacker-controlled :path values against server.targetOrigin in #onIncomingRequest in packages/@happy-dom/server-renderer/src/ServerRendererServer.ts without confirming that the resolved origin remains trusted before calling fetch. A protocol-relative path can change the destination to an arbitrary HTTP or HTTPS endpoint reachable by the server, including local and internal services, and the proxy relays the fetched response headers and body to the requester. This issue is fixed in version 21.0.2.

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:U/C:H/I:N/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Affected Versions

capricorn86 / happy-dom

< 21.0.2

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/capricorn86/happy-dom/security/advisories/GHSA-pmf4-3xr3-xjhg github.com: https://github.com/capricorn86/happy-dom/pull/2520 github.com: https://github.com/capricorn86/happy-dom/commit/1f3ffdf634231361de1a2acb629b4fe8ee1bd85d github.com: https://github.com/capricorn86/happy-dom/releases/tag/v21.0.2