High · CVSS 7.3CVE-2026-54702

Markdown Preview Enhanced: Blind Command Dispatch via Unvalidated Webview Message HandlerCVE-2026-54702

Answer in brief

CVE-2026-54702 records a High severity (CVSS 7.3) vulnerability in Markdown Preview Enhanced: Blind Command Dispatch via Unvalidated Webview Message Handler. The current sources do not mark it as known exploited. The current feed maps shd101wyy/vscode-markdown-preview-enhanced (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 14, 2026Updated Oct 14, 2026Source checked Oct 14, 2026First seen by HOL Oct 14, 2026Material review Oct 14, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.3
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 7.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps shd101wyy/vscode-markdown-preview-enhanced (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
shd101wyy/vscode-markdown-preview-enhancedgeneric	<0.8.30	0.8.30

Recommended response

Check inventory. Check lockfiles and deployed manifests for shd101wyy/vscode-markdown-preview-enhanced.
Review the reported fix. Update shd101wyy/vscode-markdown-preview-enhanced to 0.8.30 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Oct 14, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 14, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 14, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.