U.S. flag   An official website of the United States government
Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock (Dot gov) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-33943 Detail

Description

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. In versions 15.10.0 through 20.8.7, a code injection vulnerability in `ECMAScriptModuleCompiler` allows an attacker to achieve Remote Code Execution (RCE) by injecting arbitrary JavaScript expressions inside `export { }` declarations in ES module scripts processed by happy-dom. The compiler directly interpolates unsanitized content into generated code as an executable expression, and the quote filter does not strip backticks, allowing template literal-based payloads to bypass sanitization. Version 20.8.8 fixes the issue.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

By selecting these links, you will be leaving NIST webspace. We have provided these links to other web sites because they may have information that would be of interest to you. No inferences should be drawn on account of other sites being referenced, or not, from this page. There may be other web sites that are more appropriate for your purpose. NIST does not necessarily endorse the views expressed, or concur with the facts presented on these sites. Further, NIST does not endorse any commercial products that may be mentioned on these sites. Please address comments about this page to [email protected].

URL Source(s) Tag(s)
https://access.redhat.com/security/cve/CVE-2026-33943 redhat-SADP
https://bugzilla.redhat.com/show_bug.cgi?id=2452522 redhat-SADP
https://github.com/capricorn86/happy-dom/commit/5437fdf8f13adb9590f9f52616d9f69c3ee8db3c GitHub, Inc. Patch 
https://github.com/capricorn86/happy-dom/releases/tag/v20.8.8 GitHub, Inc. Product  Release Notes 
https://github.com/capricorn86/happy-dom/security/advisories/GHSA-6q6h-j7hj-3r64 CISA-ADP, GitHub, Inc. Exploit  Vendor Advisory 
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33943.json redhat-SADP

Weakness Enumeration

CWE-ID CWE Name Source
CWE-94 Improper Control of Generation of Code ('Code Injection') GitHub, Inc.  
CWE-917 Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression La redhat-SADP  

Known Affected Software Configurations Switch to CPE 2.2

CPEs loading, please wait.

Denotes Vulnerable Software
Are we missing a CPE here? Please let us know.

Change History

7 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-33943
NVD Published Date:
03/27/2026
NVD Last Modified:
07/14/2026
Source:
GitHub, Inc.