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

Why it is Amber

• CVSS 8.8 high
• Remotely exploitable without logging in

References

• https://github.com/shd101wyy/crossnote/commit/5588ca2121c3da43fe331575dc5cf4ef347b91ee
• https://github.com/shd101wyy/crossnote/pull/442
• https://github.com/shd101wyy/crossnote/releases/tag/0.9.29
• https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/dcd80281c986293b93d9f1af34ced64dcb230c77
• https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2318
• https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.28
• https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-7v6f-3vq6-r373

Original description

Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code. Prior to 0.8.28, Markdown Preview Enhanced preview-link handling passes a decoded, Markdown-controlled link target to a Windows file-opening helper that invokes child_process.exec with the start command. When a Windows user opens an untrusted Markdown file and clicks a crafted external or unsupported-scheme link, shell metacharacters in the decoded target are interpreted by cmd.exe as command separators, allowing an attacker-selected command to run with the privileges of the current VS Code user. The attack requires one normal preview-link click but does not require malicious workspace configuration, script execution to be enabled, or additional files. This issue is fixed in version 0.8.28.