CVE-2026-54702

Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code

Risk score: 46/100
CVSS: 7.3 v4.0
Exploit chance (30 days): 0.2%
Published: 14 Oct 2026

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What to know

What it is: Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code. Prior to 0.8.30, the webview message handler in src/preview-provider.ts accepts an attacker-controlled command value and attacker-controlled args, constructs a command in the _crossnote namespace, and invokes vscode.commands.executeComma…
Affected: See advisory
Fix: Upgrade the product to 0.8.30 or later.
Exploitation: No known exploitation

Why it is Yellow

CVSS 7.3 high

References

Original description

Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code. Prior to 0.8.30, the webview message handler in src/preview-provider.ts accepts an attacker-controlled command value and attacker-controlled args, constructs a command in the _crossnote namespace, and invokes vscode.commands.executeCommand without an allowlist or type validation. JavaScript already executing in the preview webview can use this bridge to invoke privileged extension commands, including file modification, code-chunk execution, export-tool execution, and arbitrary URL opening, with attacker-selected arguments. Exploitation requires a separate webview JavaScript execution path, such as the independently tracked .crossnote/head.html injection, but no further authorization check protects the extension-host command boundary. This issue is fixed in version 0.8.30.

Last activity 14 Oct 2026. Patch Forecast updates every hour.