CVE-2026-54701
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
References
- https://github.com/shd101wyy/crossnote/commit/8c55a2ba3365712a1caa4abeece0383bc2994d48
- https://github.com/shd101wyy/crossnote/pull/444
- https://github.com/shd101wyy/crossnote/releases/tag/0.9.31
- https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/8bc848b6cbb42b9f35a0f95f7c3bf29b8302970e
- https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2323
- https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.30
- https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-mcwg-4j78-qwv3
CWEs
CWE-79
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.