shd101wyy Markdown Preview Enhanced up to 0.8.29 Webview Message src/preview-provider.ts vscode.commands.executeCommand command/args improper authorization

Summaryinfo

A vulnerability was found in shd101wyy Markdown Preview Enhanced up to 0.8.29 and classified as critical. This affects the function vscode.commands.executeCommand of the file src/preview-provider.ts of the component Webview Message Handler. Executing a manipulation of the argument command/args can lead to improper authorization. This vulnerability is registered as CVE-2026-54702. It is possible to launch the attack remotely. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability has been found in shd101wyy Markdown Preview Enhanced up to 0.8.29 and classified as critical. This vulnerability affects the function vscode.commands.executeCommand of the file src/preview-provider.ts of the component Webview Message Handler. The manipulation of the argument command/args with an unknown input leads to a improper authorization vulnerability. The CWE definition for the vulnerability is CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-54702 since 06/16/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1548.002.

Upgrading to version 0.8.30 eliminates this vulnerability.

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Productinfo

Vendor

• shd101wyy

Name

• Markdown Preview Enhanced

Version

• 0.8.0
• 0.8.1
• 0.8.2
• 0.8.3
• 0.8.4
• 0.8.5
• 0.8.6
• 0.8.7
• 0.8.8
• 0.8.9
• 0.8.10
• 0.8.11
• 0.8.12
• 0.8.13
• 0.8.14
• 0.8.15
• 0.8.16
• 0.8.17
• 0.8.18
• 0.8.19
• 0.8.20
• 0.8.21
• 0.8.22
• 0.8.23
• 0.8.24
• 0.8.25
• 0.8.26
• 0.8.27
• 0.8.28
• 0.8.29

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