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.
History

Fri, 05 Jun 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Fri, 05 Jun 2026 18:15:00 +0000

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'}


cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-06-05T19:03:27.311Z

Reserved: 2026-06-05T16:54:32.159Z

Link: CVE-2026-50733

cve-icon Vulnrichment

Updated: 2026-06-05T19:03:10.502Z

cve-icon NVD

Status : Deferred

Published: 2026-06-05T18:17:34.050

Modified: 2026-06-05T18:59:54.823

Link: CVE-2026-50733

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.