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PatchSiren cyber security CVE debrief

CVE-2026-49493 shd101wyy CVE debrief

CVE-2026-49493 is a HIGH severity vulnerability in Markdown Preview Enhanced before 0.8.28. The vulnerability allows arbitrary code execution via bitfield fenced code blocks. 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. The vulnerability was fixed in version 0.8.28 by parsing bitfield register definitions with JSON5.parse(), as they are purely data.

Vendor
shd101wyy
Product
Markdown Preview Enhanced
CVSS
HIGH 8.6
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-05
Original CVE updated
2026-06-05
Advisory published
2026-06-05
Advisory updated
2026-06-05

Who should care

Users of Markdown Preview Enhanced before version 0.8.28 should update to version 0.8.28 or later to mitigate this vulnerability.

Technical summary

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.

Defensive priority

HIGH

Recommended defensive actions

  • Update Markdown Preview Enhanced to version 0.8.28 or later.
  • Avoid rendering or exporting untrusted markdown documents.

Evidence notes

Vendor and product information could not be confirmed.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-49493 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-49493

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-49493 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-49493

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.