CVE-2026-34226
Happy DOM is a JavaScript implementation of a web browser without its graphical user interface.
Published Mar 27, 2026 · corrected/updated Aug 19, 2026 · capricorn86 happy dom · evidence confidence medium
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 ( ) instead of the request target URL when is used. This can leak cookies from origin A to destination B. Version 20.8.9 fixes the issue.
Grounded briefings
Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.
Executive
CVE-2026-34226 is a high public vulnerability record for capricorn86 happy dom. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.
System administrator
Identify whether capricorn86 happy dom is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: capricorn86/happy dom. Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.
Security analyst
Signals on file: CVSS 7.5. It is not currently listed in the CISA Known Exploited catalog. Weakness classes: CWE-201, CWE-359. Sources contributing to this record: cve_org, nvd. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.
Exploitation and remediation
Exploitation evidence
Not listed as known exploited in CISA KEV. Not in the CISA KEV catalog.
Patch and remediation
No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Mar 27, 2026 · NIST NVD
Detected
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 ( ) instead of the request target URL when is used. This can leak cookies from origin A to destination B. Version 20.8.9 fixes the issue.
Aug 19, 2026 · NIST NVD
Updated
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 ( ) instead of the request target URL when is used. This can leak cookies from origin A to destination B. Version 20.8.9 fixes the issue.
Affected
- cpe capricorn86/happy domversion unspecified
Sources
- CVE.orgVulnerability recordCVE-2026-34226
Official CVE identifier
cve.org - NIST NVDVulnerability recordCVE-2026-34226
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 ( ) instead of the request target URL when is used. Th
nvd.nist.gov