CVE-2026-54701
Markdown Preview Enhanced: Stored XSS via Unsanitized `.crossnote/head.html` Injection in Webview
- State
- Published
- Severity
- 6.9 Medium
- Published
- Oct 14, 2026
- Updated
- Oct 20, 2026
- Reserved
- Jun 15, 2026
Description
Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code. Prior to 0.8.30, Markdown Preview Enhanced reads repository-controlled .crossnote/head.html content and passes it through resolvePathsInHeader before inserting it into the head of the preview webview document without removing executable content. Script-capable markup executes while the document loads, before the React application and DOMPurify initialize, and can access acquireVsCodeApi to send messages from the webview to the extension host. Opening a Markdown preview in a malicious repository is sufficient to trigger the injected content, and no additional click within the notification or preview is required. This issue is fixed in version 0.8.30.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.9 Medium | CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N | GitHub_M |
Weaknesses
- CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Products
| Product | Versions |
|---|---|
vscode-markdown-preview-enhancedshd101wyy |
|
References
- https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-mcwg-4j78-qwv3
- https://github.com/shd101wyy/crossnote/pull/444
- https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2323
- https://github.com/shd101wyy/crossnote/commit/8c55a2ba3365712a1caa4abeece0383bc2994d48
- https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/8bc848b6cbb42b9f35a0f95f7c3bf29b8302970e
- https://github.com/shd101wyy/crossnote/releases/tag/0.9.31
- https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.30
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.