{"schema":"threatline.record/2","record":{"id":"CVE-2026-54566","aliases":["GHSA-427h-jhpr-8jch"],"summary":"Markdown Preview Enhanced: Remote Code Execution via VM Sandbox Escape in `.crossnote/config.js` and `.crossnote/parser.js`","details":"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.","categories":["Unclassified"],"product":"vscode-markdown-preview-enhanced","vendor":"shd101wyy","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-54566","source_modified_at":"2026-10-14T19:45:22.736Z","fetched_at":"2026-10-23T18:48:36.087640Z","product":"vscode-markdown-preview-enhanced","vendor":"shd101wyy","versions":[{"version":"< 0.8.29","status":"affected"}],"defaultStatus":null}],"fixed_versions":[],"cvss":8.5,"severity":"High","kev":{"listed":false},"epss":{"probability":0.00296,"percentile":0.21149,"score_date":"2026-10-23"},"published_at":"2026-10-14T19:08:43.663Z","modified_at":"2026-10-14T19:45:22.736Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-54566","fetched_at":"2026-10-23T18:48:36.087640Z","source_modified_at":"2026-10-14T19:45:22.736Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-54566","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-427h-jhpr-8jch","tags":["exploit"]},{"source":"CVE List","url":"https://github.com/shd101wyy/crossnote/pull/443","tags":["x_refsource_MISC"]},{"source":"CVE List","url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2320","tags":["x_refsource_MISC"]},{"source":"CVE List","url":"https://github.com/shd101wyy/crossnote/commit/e4890d64502e53b717cce0cb73f1a78b244dc640","tags":["x_refsource_MISC"]},{"source":"CVE List","url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/0d4010988c6ae56a38c6dec4a7509cbd5a7dcb4c","tags":["x_refsource_MISC"]},{"source":"CVE List","url":"https://github.com/shd101wyy/crossnote/releases/tag/0.9.30","tags":["x_refsource_MISC"]},{"source":"CVE List","url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.29","tags":["x_refsource_MISC"]}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","ssvc":{"exploitation":"poc","automatable":"no","technical_impact":"total","assessed_at":"2026-10-14T19:44:50.050593Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2026-10-14T19:45:22.736Z","content_hash":"ee1ef5b74b8c353b27dd94519a3cc43258915b78d72116e00656533298239080"}}