FKIE_CVE-2026-54566

Vulnerability from fkie_nvd - Published: 2026-10-14 20:17 - Updated: 2026-10-14 20:17
Severity
8.5 (High) - 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
Summary
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.
References
security-advisories@github.comhttps://github.com/shd101wyy/crossnote/commit/e4890d64502e53b717cce0cb73f1a78b244dc640
security-advisories@github.comhttps://github.com/shd101wyy/crossnote/pull/443
security-advisories@github.comhttps://github.com/shd101wyy/crossnote/releases/tag/0.9.30
security-advisories@github.comhttps://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/0d4010988c6ae56a38c6dec4a7509cbd5a7dcb4c
security-advisories@github.comhttps://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2320
security-advisories@github.comhttps://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.29
security-advisories@github.comhttps://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-427h-jhpr-8jch
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-427h-jhpr-8jch
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "vscode-markdown-preview-enhanced",
          "vendor": "shd101wyy",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.8.29"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "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."
    }
  ],
  "id": "CVE-2026-54566",
  "lastModified": "2026-10-14T20:17:47.403",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "LOCAL",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 8.5,
          "baseSeverity": "HIGH",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "PASSIVE",
          "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",
          "version": "4.0",
          "vulnAvailabilityImpact": "HIGH",
          "vulnConfidentialityImpact": "HIGH",
          "vulnIntegrityImpact": "HIGH",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-54566",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-10-14T19:44:50.050593Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-10-14T20:17:47.403",
  "references": [
    {
      "source": "security-advisories@github.com",
      "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": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-427h-jhpr-8jch"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-94"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}



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