CVE-2026-33943

Description

A flaw was found in Happy DOM, a JavaScript implementation of a web browser. This vulnerability allows a remote attacker to achieve Remote Code Execution (RCE) by injecting arbitrary JavaScript expressions. The ECMAScriptModuleCompiler component fails to properly sanitize content within export { } declarations in ES module scripts, leading to the direct execution of malicious code.

Mitigation

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Common Vulnerability Scoring System (CVSS) Score Details

Info alert:Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).

The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 Score Breakdown

Red HatNVDcve.org
Base Score8.89.88.8
Attack VectorNetworkNetworkNetwork
Attack ComplexityLowLowLow
Privileges RequiredNoneNoneNone
User InteractionRequiredNoneRequired
ScopeUnchangedUnchangedUnchanged
ConfidentialityHighHighHigh
Integrity ImpactHighHighHigh
Availability ImpactHighHighHigh

Vector

Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Understanding the Weakness (CWE)

CWE-917

Confidentiality

Technical Impact: Read Application Data

Integrity

Technical Impact: Execute Unauthorized Code or Commands

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