VulnerabilityAwaiting Analysis

CVE-2026-54702

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…

HIGH 7.3EPSS 0.31%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.31%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 4.0: 7.3 HIGHCVSS: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/M
EPSS: 0.31% probability · 24th percentile
Public exploits: None in Exploit-DB
CISA KEV: Not listed
Weakness: CWE-749
Source: security-advisories@github.com

EPSS trend

EPSS moved from 0.2% on 15 October 2026 to 0.3% on 26 October 2026.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.