Unauthenticated HTTP/2 Request Vulnerability in Happy DOM JavaScript Implementation
CVE-2026-118659

7.5HIGH

Key Information:

Vendor

Capricorn86

Status
Happy-dom
Vendor
CVE Published:
28 October 2026

What is CVE-2026-118659?

The Happy DOM server-renderer package prior to version 21.0.2 contains a flaw allowing unauthenticated HTTP/2 requests. The ServerRendererServer improperly resolves attacker-controlled :path values against server.targetOrigin without verifying trust. This vulnerability enables an attacker to redirect requests to arbitrary HTTP or HTTPS endpoints, potentially exposing sensitive data through relayed responses from internal services.

Affected Version(s)

happy-dom < 21.0.2

References

https://github.com/capricorn86/happy-dom/security/advisor...
x_refsource_CONFIRM
https://github.com/capricorn86/happy-dom/pull/2520
x_refsource_MISC
https://github.com/capricorn86/happy-dom/commit/1f3ffdf63...
x_refsource_MISC

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
High
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.