CVE-2026-118659 - Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Prior to 21.0.2, the Hap
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.
HIGH
Severity & confidence
Source severityhigh
Platform severityhigh
Confidencehigh
Exploitationunknown
CVSS7.5
Affected
Reporting sources (1)
NIST NVD - National Vulnerability Database
Timeline & provenance
Published2026-10-28T21:16:55
Last updated2026-10-31T21:01:43
Ingested2026-10-31T11:24:28
FreshnessNEAR-REAL-TIME
Threat typevulnerability
Recommended action
No recommended action published with this item - review the original source.
Next steps
- Identify affected systems in your environment.
- Apply the vendor patch or mitigation guidance.
- Review logs for indicators described in the advisory.
- Follow the affected vendor/product to track updates.
Confidence explanation
Reported by a government or cert-grade source (CISA, NCSC, NVD, ENISA, MSRC).
Source type: standards ยท Original: NIST NVD - National Vulnerability Database
