Happy DOM's fetch credentials include uses page-origin cookies instead of target-origin cookies
Priority HIGH 72CWE-201Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Partial Red Hat: 1 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-201.
Summary
Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Versions prior to 20.8.9 may attach cookies from the current page origin (`window.location`) instead of the request target URL when `fetch(..., { credentials: "include" })` is used. This can leak cookies from origin A to destination B. Version 20.8.9 fixes the issue.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00466 40th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial happy-dom (capricorn86): 20.8.9happy-dom (npm): 20.8.9Red Hat: 1 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| capricorn86 | happy-dom | before 20.8.9 | 20.8.9 | Patch available | CNA |
| — | happy-dom (npm) | before 20.8.9 | 20.8.9 | Patch available | GHSA-w4gp-fjgq-3q4g |
- happy-dom Vendorcapricorn86 Affected before 20.8.9 Fixed in 20.8.9 Patch available CNA
- happy-dom (npm) Vendor— Affected before 20.8.9 Fixed in 20.8.9 Patch available GHSA-w4gp-fjgq-3q4g
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:capricorn86:happy_dom:*:*:*:*:*:node.js:*:* | before 20.8.9 | Vulnerable | capricorn86 |
- cpe:2.3:a:capricorn86:happy_dom:*:*:*:*:*:node.js:*:* Versions before 20.8.9 Vulnerable ·capricorn86
Remediation
- Fix · CNA happy-dom (capricorn86) Fixed in 20.8.9
- Fix · GHSA-w4gp-fjgq-3q4g happy-dom (npm) Fixed in 20.8.9 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Ansible Automation Platform 2 | Affected | No fix planned: Will not fix |
Not affected: 1 product
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-02 Threatist record created from CVE-2026-34226
- 2026-10-03 Alias added: GHSA-w4gp-fjgq-3q4g
References
Patch 3
More capricorn86 Happy Dom vulnerabilities
- TI-2026-26294 Happy DOM ECMAScriptModuleCompiler: unsanitized export names are interpolated as executable code CVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-34226 · CVE Program
- CVE-2026-34226 · NVD
- FIRST EPSS
- GHSA-w4gp-fjgq-3q4g · GitHub Advisory Database · CC BY 4.0
- CVE-2026-34226 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences