Markdown Preview Enhanced: Blind Command Dispatch via Unvalidated Webview Message Handler

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-54702
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-14 20:17:47 UTC
Updated2026-10-16 16:00:33 UTC
DescriptionMarkdown 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.

Risk And Classification

Primary CVSS: v4.0 7.3 HIGH from [email protected]

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-749 | CWE-749 CWE-749: Exposed Dangerous Method or Function

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary7.3HIGHCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/C...
4.0CNADECLARED7.3HIGHCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
Passive
Confidentiality
High
Integrity
High
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Shd101wyy Vscode-markdown-preview-enhanced affected < 0.8.30 Not specified

References

ReferenceSourceLinkTags
github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisorie... 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/8bc848b6cbb... [email protected] github.com
github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.30 [email protected] github.com
github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2323 [email protected] github.com
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