shd101wyy vscode-markdown-preview-enhanced up to 0.8.29 Markdown Preview head.html _crossnote.updateMarkdown cross site scripting

Summaryinfo

A vulnerability categorized as problematic has been discovered in shd101wyy vscode-markdown-preview-enhanced up to 0.8.29. This impacts the function _crossnote.updateMarkdown of the file head.html of the component Markdown Preview. The manipulation results in cross site scripting. This vulnerability is known as CVE-2026-54703. It is possible to launch the attack remotely. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in shd101wyy vscode-markdown-preview-enhanced up to 0.8.29. Affected is the function _crossnote.updateMarkdown of the file head.html of the component Markdown Preview. The manipulation with an unknown input leads to a cross site scripting vulnerability. CWE is classifying the issue as CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. This is going to have an impact on integrity. CVE summarizes:

Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code. Prior to 0.8.30, the _crossnote.updateMarkdown command in Markdown Preview Enhanced accepts an arbitrary URI and attacker-controlled content, then passes them to vscode.workspace.fs.writeFile without validating that the target is the Markdown file represented by the current preview. JavaScript already executing in the preview webview can invoke this command through the extension message bridge and write any file permitted by the VS Code user's operating-system privileges, including user configuration, startup, source, and build files. This file-write vulnerability requires a separate webview JavaScript execution path, such as the independently tracked head.html injection and blind command-dispatch weaknesses. This issue is fixed in version 0.8.30.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-54703 since 06/16/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1059.007 by the MITRE ATT&CK project.

By approaching the search of inurl:head.html it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 0.8.30 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• shd101wyy

Name

• vscode-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

Website

• Product: https://github.com/shd101wyy/vscode-markdown-preview-enhanced/

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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