What’s Vulnerable › Vulnerabilities

CVE-2026-49493: Markdown Preview Enhanced Arbitrary Code Execution via Bitfield interpretJS()

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-05 · updated 2026-10-26
• Weakness: CWE-94

Description

Markdown Preview Enhanced before 0.8.28 parses Bitfield fenced code blocks with interpretJS(), which evaluates the block content as code via vm.runInNewContext(), allowing arbitrary code execution. A crafted markdown document containing a malicious bitfield code block executes attacker-controlled code on the server side when the document is rendered or exported. Fixed in 0.8.28 by parsing bitfield register definitions with JSON5.parse(), since they are purely data.

Affected products

• shd101wyy Markdown Preview Enhanced: before 0.8.28 — fixed in 0.8.28

How to fix

Upgrade to a fixed version: shd101wyy Markdown Preview Enhanced 0.8.28. Check the vendor advisory for mitigations.

References

• https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.28
• https://www.vulncheck.com/advisories/markdown-preview-enhanced-arbitrary-code-execution-via-bitfield-interpretjs

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