HOMEVULNERABILITIESCVE-2026-34226
HIGH

CVE-2026-34226

CWE-201Published: March 27, 2026· Updated: Apr 1, 2026

7.5
CVSS v3.1
EPSS:0.03%probability of exploitation in 30 daysPercentile:9.2th

Official Description

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.

NVD Source

Technical Analysis

CVE-2026-34226 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), with a CVSS base score of 7.5.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityNone
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected Vendors & Products

capricorn861 product
happy dom
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://github.com/capricorn86/happy-dom/blob/f8d8cad41e9722fab9eefb9dfb3cca696462e908/packages/happy-dom/src/fetch/utilities/FetchRequestHeaderUtility.ts
PATCHhttps://github.com/capricorn86/happy-dom/commit/68324c21d7b98f53f7bb5a7b3e185bda7106e751
PATCHhttps://github.com/capricorn86/happy-dom/pull/2117
ADVISORYhttps://github.com/capricorn86/happy-dom/security/advisories/GHSA-w4gp-fjgq-3q4g

All References (5)

→
https://github.com/capricorn86/happy-dom/blob/f8d8cad41e9722fab9eefb9dfb3cca696462e908/packages/happy-dom/src/fetch/utilities/FetchRequestHeaderUtility.tsPatch
→
https://github.com/capricorn86/happy-dom/commit/68324c21d7b98f53f7bb5a7b3e185bda7106e751Patch
→
https://github.com/capricorn86/happy-dom/pull/2117Issue Tracking · Patch
→
https://github.com/capricorn86/happy-dom/releases/tag/v20.8.9Product · Release Notes
→
https://github.com/capricorn86/happy-dom/security/advisories/GHSA-w4gp-fjgq-3q4gExploit · Vendor Advisory

Quick Facts

CVE IDCVE-2026-34226
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-201
CISA KEVNo
EPSS (30d)0.03%
Affected1 vendor
PublishedMar 27, 2026

Related CVEs (CWE-201)

CVE-2026-39912
9.1
CVE-2025-11500
8.7
CVE-2026-5483
8.5
CVE-2026-54848
8.3
CVE-2026-46481
8.3
CVE-2026-32829
8.2

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2026-34226 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
← All Vulnerabilities·Search for CVE-2026-34226·NVD