---
id: CVE-2026-50733
title: Markdown Preview Enhanced Arbitrary Code Execution via WaveDrom eval()
summary: >-
  Markdown Preview Enhanced before 0.8.28 parses WaveDrom diagrams by evaluating
  untrusted markdown content with eval(), allowing arbitrary JavaScript
  execution. The flaw affects every render path - the live preview (window.eval)
  and prese…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-95
vendor: shd101wyy
product: Markdown Preview Enhanced
affected:
  - markdown_preview_enhanced < 0.8.28
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-06-05T19:03:16.138729Z'
exploitAvailable: true
published: '2026-06-05'
updated: '2026-11-08'
sourceUpdated: '2026-11-08T14:05:02.848Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-50733'
references:
  - url: >-
      https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.28
    label: Markdown Preview Enhanced 0.8.28 Release Notes
  - url: 'https://github.com/shd101wyy/vscode-markdown-preview-enhanced/issues/2315'
    label: 'Issue #2315'
  - url: >-
      https://www.vulncheck.com/advisories/markdown-preview-enhanced-arbitrary-code-execution-via-wavedrom-eval
    label: >-
      VulnCheck Advisory: Markdown Preview Enhanced Arbitrary Code Execution via
      WaveDrom eval()
tags:
  - cve.org
  - exploit-available
epss: 0.00667
epssPercentile: 0.52137
ingestedAt: '2026-11-08T14:51:22.379Z'
---

## Overview

Markdown Preview Enhanced before 0.8.28 parses WaveDrom diagrams by evaluating untrusted markdown content with eval(), allowing arbitrary JavaScript execution. The flaw affects every render path - the live preview (window.eval) and presentation mode plus HTML export (the bundled WaveDrom.ProcessAll()/eva() helpers) - and can also be triggered through a <script type="WaveDrom"> element injected via raw HTML in markdown. When a victim previews or exports a crafted markdown document, an attacker can execute arbitrary code, leading to arbitrary file write. Fixed in 0.8.28 by parsing with JSON5.parse() and sanitizing WaveDrom data scripts to inert strict JSON.

## Affected

- `markdown_preview_enhanced < 0.8.28`

## Remediation

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