CVE-2026-49493: SHD101WYY Markdown Preview Enhanced

High severity, CVSS 8.8. EPSS: 0.6% chance of exploitation in the next 30 days.

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)

Published 2026-06-05. Last modified 2026-06-17.