{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-54566","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-06-15T19:15:27.342Z","datePublished":"2026-10-14T19:08:43.663Z","dateUpdated":"2026-10-14T19:45:22.736Z"},"containers":{"cna":{"title":"Markdown Preview Enhanced: Remote Code Execution via VM Sandbox Escape in `.crossnote/config.js` and `.crossnote/parser.js`","problemTypes":[{"descriptions":[{"cweId":"CWE-94","lang":"en","description":"CWE-94: Improper Control of Generation of Code ('Code Injection')","type":"CWE"}]}],"metrics":[{"cvssV4_0":{"attackVector":"LOCAL","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"PASSIVE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.5,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","version":"4.0"}}],"references":[{"name":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-427h-jhpr-8jch","tags":["x_refsource_CONFIRM"],"url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-427h-jhpr-8jch"},{"name":"https://github.com/shd101wyy/crossnote/pull/443","tags":["x_refsource_MISC"],"url":"https://github.com/shd101wyy/crossnote/pull/443"},{"name":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2320","tags":["x_refsource_MISC"],"url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2320"},{"name":"https://github.com/shd101wyy/crossnote/commit/e4890d64502e53b717cce0cb73f1a78b244dc640","tags":["x_refsource_MISC"],"url":"https://github.com/shd101wyy/crossnote/commit/e4890d64502e53b717cce0cb73f1a78b244dc640"},{"name":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/0d4010988c6ae56a38c6dec4a7509cbd5a7dcb4c","tags":["x_refsource_MISC"],"url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/0d4010988c6ae56a38c6dec4a7509cbd5a7dcb4c"},{"name":"https://github.com/shd101wyy/crossnote/releases/tag/0.9.30","tags":["x_refsource_MISC"],"url":"https://github.com/shd101wyy/crossnote/releases/tag/0.9.30"},{"name":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.29","tags":["x_refsource_MISC"],"url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.29"}],"affected":[{"vendor":"shd101wyy","product":"vscode-markdown-preview-enhanced","versions":[{"version":"< 0.8.29","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-10-14T19:08:43.663Z"},"descriptions":[{"lang":"en","value":"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."}],"source":{"advisory":"GHSA-427h-jhpr-8jch","discovery":"UNKNOWN"}},"adp":[{"references":[{"url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-427h-jhpr-8jch","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-14T19:44:50.050593Z","id":"CVE-2026-54566","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-10-14T19:45:22.736Z"}}]}}