Markdown Preview Enhanced

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.

Published: 2026-06-05T17:49:53.631Z
Updated: 2026-11-08T14:05:02.848Z

Markdown Preview Enhanced before 0.8.28 parses Bitfield fenced code blocks with interpretJS(), which evaluates the block content as code via vm.runInNewContext(), allowing arbitrary code execution. A crafted markdown document containing a malicious bitfield code block executes attacker-controlled code on the server side when the document is rendered or exported. Fixed in 0.8.28 by parsing bitfield register definitions with JSON5.parse(), since they are purely data.

Published: 2026-06-05T17:49:52.826Z
Updated: 2026-11-08T14:04:54.235Z

Markdown Preview Enhanced before 0.8.28 opens external files and links from the preview through a shell and does not validate untrusted inputs taken from the markdown document - the diagram filename attribute, imported file paths, and the latex_engine code-chunk attribute. On Windows, a crafted markdown document can inject operating system commands that execute when the document is previewed. Fixed in 0.8.28 by passing these inputs as literal arguments instead of through a shell and validating them before use.

Published: 2026-06-05T17:49:52.057Z
Updated: 2026-11-08T14:04:53.515Z