CVE-2026-50733CWE-95

Markdown Preview Enhanced Arbitrary Code Execution via WaveDrom eval()

High · published June 5, 2026

CVSS v4.0
8.6
EPSS
1%
Percentile
50.2
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
8.6 · HIGH
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
EPSS
0.00644 · 50.2th percentile
Weakness
CWE-95 · Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection')
Published
2026-06-05T17:49Z
EPSS history
Timeline
  • 05 JUN 17:49Z
    Markdown Preview Enhanced Arbitrary Code Execution via WaveDrom eval()
    cvelistv5