CVE-2026-54566Public exploitHinoki check available

Code execution via repository-script sandbox escape

Published Oct 14, 2026 · Updated Oct 14, 2026

Sandbox escape in Markdown Preview Enhanced before 0.8.29 allows attackers to execute OS commands via malicious repository files. The configuration and parser loaders evaluate .crossnote/config.js and .crossnote/parser.js with vm.runInNewContext, allowing prototype-chain traversal to reach the Node.js host realm. Opening a Markdown file in the malicious repository triggers evaluation without further interaction, and commands run with the victim account's privileges.

CVSS severity8.5
High
EPSS probability0.30%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Sandbox escape in Markdown Preview Enhanced before 0.8.29 allows attackers to execute OS commands via malicious repository files. The configuration and parser loaders evaluate .crossnote/config.js and .crossnote/parser.js with vm.runInNewContext, allowing prototype-chain traversal to reach the Node.js host realm. Opening a Markdown file in the malicious repository triggers evaluation without further interaction, and commands run with the victim account's privileges.

The record

CVE
CVE-2026-54566
Published
Oct 14, 2026
Updated
Oct 14, 2026
Vendor
shd101wyy
Product
Markdown Preview Enhanced
Classifications
CWE-94, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.8.29

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

shd101wyy · Markdown Preview Enhancedversion=< 0.8.29

Published CVSS scores

8.5GitHubCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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