---
id: CVE-2026-54702
title: >-
  Markdown Preview Enhanced is a Markdown preview extension for Visual Studio
  Code
summary: >-
  Markdown Preview Enhanced is a Markdown preview extension for Visual Studio
  Code. Prior to 0.8.30, the webview message handler in src/preview-provider.ts
  accepts an attacker-controlled command value and attacker-controlled args,
  construc…
severity: none
cwe:
  - CWE-749
published: '2026-10-14'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T20:17:47.737'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-54702'
references:
  - url: >-
      https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/8bc848b6cbb42b9f35a0f95f7c3bf29b8302970e
    label: security-advisories@github.com
  - url: 'https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2323'
    label: security-advisories@github.com
  - url: >-
      https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.30
    label: security-advisories@github.com
  - url: >-
      https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-83c6-hcjv-pvmg
    label: security-advisories@github.com
tags:
  - nvd
ingestedAt: '2026-10-14T20:53:12.377Z'
---

## Overview

Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code. Prior to 0.8.30, the webview message handler in src/preview-provider.ts accepts an attacker-controlled command value and attacker-controlled args, constructs a command in the _crossnote namespace, and invokes vscode.commands.executeCommand without an allowlist or type validation. JavaScript already executing in the preview webview can use this bridge to invoke privileged extension commands, including file modification, code-chunk execution, export-tool execution, and arbitrary URL opening, with attacker-selected arguments. Exploitation requires a separate webview JavaScript execution path, such as the independently tracked .crossnote/head.html injection, but no further authorization check protects the extension-host command boundary. This issue is fixed in version 0.8.30.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.