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CVE-2026-54703— Markdown Preview Enhanced: Arbitrary File Write via updateMarkdown Command Without Path Validation

Quick assessment

Affected
shd101wyy vscode-markdown-preview-enhanced
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Markdown Preview Enhanced 是 Visual Studio Code 的一款 Markdown 预览扩展。在版本 0.8.30 之前，_crossnote.updateMarkdown 命令接受任意 URI 和攻击者可控的内容，然后将这些内容传递给 vscode.workspace.fs.writeFile，而未验证目标文件是否为当前预览所对应的 Markdown 文件。已在预览 Webview 中执行的 JavaScript 代码可以通过扩展消息桥接（extension message b

CVSS 5.8 · Medium EPSS 0.22% · P11

Affected Version Matrix 1

VendorProduct Version RangeStatus
shd101wyy vscode-markdown-preview-enhanced < 0.8.30 affected
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I. Basic Information for CVE-2026-54703

Vulnerability Information
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Vulnerability Title
Markdown Preview Enhanced: Arbitrary File Write via updateMarkdown Command Without Path Validation
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
文件名或路径的外部可控制
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
shd101wyy vscode-markdown-preview-enhanced < 0.8.30 -

II. Public POCs for CVE-2026-54703

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III. Intelligence Information for CVE-2026-54703

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Patches & Fixes for CVE-2026-54703 (2)

Other References for CVE-2026-54703 (2)

Same Patch Batch · shd101wyy · 2026-10-14 · 5 CVEs total

CVE-2026-54525 8.8 HIGH Markdown Preview Enhanced: One Click RCE via Markdown Link Command Injection on Windows
CVE-2026-54566 8.5 HIGH Markdown Preview Enhanced: Remote Code Execution via VM Sandbox Escape in `.crossnote/conf
CVE-2026-54702 7.3 HIGH Markdown Preview Enhanced: Blind Command Dispatch via Unvalidated Webview Message Handler
CVE-2026-54701 6.9 MEDIUM Markdown Preview Enhanced: Stored XSS via Unsanitized `.crossnote/head.html` Injection in

IV. Related Vulnerabilities

Same product: vscode-markdown-preview-enhanced
Same vendor: shd101wyy
Same weakness: CWE-73

V. Comments for CVE-2026-54703

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