CVE-2026-54566

{"id": "CVE-2026-54566", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-54566", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2026-10-14T19:44:50.050593Z"}}], "cvssMetricV40": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 8.5, "Automatable": "NOT_DEFINED", "attackVector": "LOCAL", "baseSeverity": "HIGH", "valueDensity": "NOT_DEFINED", "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/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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "PASSIVE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "shd101wyy", "product": "vscode-markdown-preview-enhanced", "versions": [{"status": "affected", "version": "< 0.8.29"}]}]}], "published": "2026-10-14T20:17:47.403", "references": [{"url": "https://github.com/shd101wyy/crossnote/commit/e4890d64502e53b717cce0cb73f1a78b244dc640", "source": "security-advisories@github.com"}, {"url": "https://github.com/shd101wyy/crossnote/pull/443", "source": "security-advisories@github.com"}, {"url": "https://github.com/shd101wyy/crossnote/releases/tag/0.9.30", "source": "security-advisories@github.com"}, {"url": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/0d4010988c6ae56a38c6dec4a7509cbd5a7dcb4c", "source": "security-advisories@github.com"}, {"url": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2320", "source": "security-advisories@github.com"}, {"url": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.29", "source": "security-advisories@github.com"}, {"url": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-427h-jhpr-8jch", "source": "security-advisories@github.com"}, {"url": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-427h-jhpr-8jch", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Primary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-94"}]}], "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."}], "lastModified": "2026-10-16T16:00:33.533", "sourceIdentifier": "security-advisories@github.com"}