CVE-2026-50733

Markdown Preview Enhanced Arbitrary Code Execution via WaveDrom eval()

Published Jun 5, 2026 CVSS 4.0 · 8.6 High EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Shd101wyy
Shd101wyy markdown Preview Enhanced
Vendors & Products Shd101wyy
Shd101wyy markdown Preview Enhanced
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title Markdown Preview Enhanced Arbitrary Code Execution via WaveDrom eval()
First Time appeared Markdown Preview Enhanced Project
Markdown Preview Enhanced Project markdown Preview Enhanced
Weaknesses CWE-95
CPEs cpe:2.3:a:markdown_preview_enhanced_project:markdown_preview_enhanced:*:*:*:*:*:*:*:*
Vendors & Products Markdown Preview Enhanced Project
Markdown Preview Enhanced Project markdown Preview Enhanced
References
Metrics cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 8.6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Nov 8, 2026, 2:05 PM
Reserved
Jun 5, 2026, 4:54 PM
Status
Deferred
Published
Jun 5, 2026, 6:17 PM
Modified
Oct 26, 2026, 11:10 AM