{"id":"CVE-2026-54566","aliases":["EUVD-2026-101582","GHSA-427h-jhpr-8jch"],"status":"published","title":"Markdown Preview Enhanced: Remote Code Execution via VM Sandbox Escape in `.crossnote/config.js` and `.crossnote/parser.js`","description":"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.","severity":{"version":"4.0","score":8.5,"vector":"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00296,"percentile":0.22432,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-94"],"published":"2026-10-14T19:08:43Z","modified":"2026-10-28T02:30:37Z","products":[{"vendor":"shd101wyy","product":"vscode-markdown-preview-enhanced"}],"references":[{"url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-427h-jhpr-8jch","tags":["x_refsource_CONFIRM","exploit","advisory"]},{"url":"https://github.com/shd101wyy/crossnote/pull/443","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2320","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/shd101wyy/crossnote/commit/e4890d64502e53b717cce0cb73f1a78b244dc640","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/0d4010988c6ae56a38c6dec4a7509cbd5a7dcb4c","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/shd101wyy/crossnote/releases/tag/0.9.30","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.29","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54566.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54566","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-54566","title":"Markdown Preview Enhanced: Remote Code Execution via VM Sandbox Escape in `.crossnote/config.js` and `.crossnote/parser.js`","description":"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.","status":"published","published":"2026-10-14T19:08:43.663Z","modified":"2026-10-14T19:45:22.736Z","cvss":[{"version":"4.0","score":8.5,"vector":"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","level":"high","assessor":"cna"}],"cwes":["CWE-94"],"updated_at":"2026-11-02T13:38:09.774038Z"}],"euvd":[{"id":"EUVD-2026-101582","description":"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.","status":"published","published":"2026-10-14T19:08:43Z","modified":"2026-10-14T19:45:22Z","cvss":[{"version":"4.0","score":8.5,"vector":"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","level":"high"}],"updated_at":"2026-11-02T17:27:12.80866Z"}],"nvd":[{"id":"CVE-2026-54566","description":"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.","status":"published","published":"2026-10-14T20:17:47.403Z","modified":"2026-10-16T16:00:33.533Z","cvss":[{"version":"4.0","score":8.5,"vector":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"}],"cwes":["CWE-94"],"updated_at":"2026-11-02T14:12:59.328869Z"}],"osv":[{"id":"CVE-2026-54566","title":"Markdown Preview Enhanced: Remote Code Execution via VM Sandbox Escape in `.crossnote/config.js` and `.crossnote/parser.js`","description":"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.","status":"published","published":"2026-10-14T19:08:43.663Z","modified":"2026-10-28T02:30:37.193866659Z","cvss":[{"version":"4.0","score":8.5,"vector":"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","level":"high"}],"cwes":["CWE-94"],"updated_at":"2026-11-02T15:45:10.818486Z"}]}}