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Vulnerabilities

Vulnerability · CVE-2026-54566

Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code.

Published Oct 14, 2026 · catalog updated Oct 14, 2026 · Markdown Preview Enhanced is

Check if you run it

No confirmed exploitation is on record for CVE-2026-54566. EPSS is 0.30%. Act only if a listed version of Markdown Preview Enhanced is is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Markdown Preview Enhanced is).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.30%
Remediation
Advisory link
Affected products
See sources for product scope

Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code. Prior to 0.8.29, Markdown Preview Enhanced evaluates repository-controlled .crossnote/config.js and .crossnote/parser.js files with vm.runInNewContext, which does not provide a security boundary from the Node.js host realm. Opening a Markdown file in a malicious repository automatically loads these files, and prototype-chain traversal can reach the host Function constructor and process object, allowing operating-system commands to execute as the victim account without further interaction. Both configuration evaluation and parser-hook evaluation are affected, and the attack does not depend on module-scoped require being available. This issue is fixed in version 0.8.29.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-54566

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-54566. EPSS is 0.30%. Act only if a listed version of Markdown Preview Enhanced is is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-94: Code Injection. EPSS 0.30%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 14, 2026 · NIST NVD

    Detected

    Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code. Prior to 0.8.29, Markdown Preview Enhanced evaluates repository-controlled .crossnote/config.js and .crossnote/parser.js files with vm.runInNewContext, which does not provide a security boundary from the Node.js host realm. Opening a Markdown file in a malicious repository automatically loads these files, and prototy

Sources

  • CVE.orgVulnerability recordCVE-2026-54566

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-54566

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2026-54566

    Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code. Prior to 0.8.29, Markdown Preview Enhanced evaluates repository-controlled .crossnote/config.js and .crossnote/parser.js files with vm.runInNewContext, which does not provide a security boundary fro

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.