CVE-2026-54702 (GCVE-0-2026-54702)

Vulnerability from cvelistv5 – Published: 2026-10-14 19:13 – Updated: 2026-10-14 19:13
VLAI
Title
Markdown Preview Enhanced: Blind Command Dispatch via Unvalidated Webview Message Handler
Summary
Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code. Prior to 0.8.30, the webview message handler in src/preview-provider.ts accepts an attacker-controlled command value and attacker-controlled args, constructs a command in the _crossnote namespace, and invokes vscode.commands.executeCommand without an allowlist or type validation. JavaScript already executing in the preview webview can use this bridge to invoke privileged extension commands, including file modification, code-chunk execution, export-tool execution, and arbitrary URL opening, with attacker-selected arguments. Exploitation requires a separate webview JavaScript execution path, such as the independently tracked .crossnote/head.html injection, but no further authorization check protects the extension-host command boundary. This issue is fixed in version 0.8.30.
Severity
7.3 (High)
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CWE
  • CWE-749 - Exposed Dangerous Method or Function
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7637 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
shd101wyy vscode-markdown-preview-enhanced Affected: < 0.8.30
guessed Create a notification for this product.
Show details on NVD website
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "vscode-markdown-preview-enhanced",
          "vendor": "shd101wyy",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.8.30"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code. Prior to 0.8.30, the webview message handler in src/preview-provider.ts accepts an attacker-controlled command value and attacker-controlled args, constructs a command in the _crossnote namespace, and invokes vscode.commands.executeCommand without an allowlist or type validation. JavaScript already executing in the preview webview can use this bridge to invoke privileged extension commands, including file modification, code-chunk execution, export-tool execution, and arbitrary URL opening, with attacker-selected arguments. Exploitation requires a separate webview JavaScript execution path, such as the independently tracked .crossnote/head.html injection, but no further authorization check protects the extension-host command boundary. This issue is fixed in version 0.8.30."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "LOCAL",
            "baseScore": 7.3,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "PASSIVE",
            "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-749",
              "description": "CWE-749: Exposed Dangerous Method or Function",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-14T19:13:58.946Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-83c6-hcjv-pvmg",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-83c6-hcjv-pvmg"
        },
        {
          "name": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2323",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2323"
        },
        {
          "name": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/8bc848b6cbb42b9f35a0f95f7c3bf29b8302970e",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/8bc848b6cbb42b9f35a0f95f7c3bf29b8302970e"
        },
        {
          "name": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.30",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.30"
        }
      ],
      "source": {
        "advisory": "GHSA-83c6-hcjv-pvmg",
        "discovery": "UNKNOWN"
      },
      "title": "Markdown Preview Enhanced: Blind Command Dispatch via Unvalidated Webview Message Handler"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-54702",
    "datePublished": "2026-10-14T19:13:58.946Z",
    "dateReserved": "2026-06-15T22:58:06.563Z",
    "dateUpdated": "2026-10-14T19:13:58.946Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "vscode-markdown-preview-enhanced",
                "vendor": "shd101wyy",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003c 0.8.30"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code. Prior to 0.8.30, the webview message handler in src/preview-provider.ts accepts an attacker-controlled command value and attacker-controlled args, constructs a command in the _crossnote namespace, and invokes vscode.commands.executeCommand without an allowlist or type validation. JavaScript already executing in the preview webview can use this bridge to invoke privileged extension commands, including file modification, code-chunk execution, export-tool execution, and arbitrary URL opening, with attacker-selected arguments. Exploitation requires a separate webview JavaScript execution path, such as the independently tracked .crossnote/head.html injection, but no further authorization check protects the extension-host command boundary. This issue is fixed in version 0.8.30."
          }
        ],
        "id": "CVE-2026-54702",
        "lastModified": "2026-10-14T20:17:47.737",
        "metrics": {
          "cvssMetricV40": [
            {
              "cvssData": {
                "Automatable": "NOT_DEFINED",
                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
                "attackComplexity": "LOW",
                "attackRequirements": "PRESENT",
                "attackVector": "LOCAL",
                "availabilityRequirement": "NOT_DEFINED",
                "baseScore": 7.3,
                "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:P/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"
            }
          ]
        },
        "published": "2026-10-14T20:17:47.737",
        "references": [
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/8bc848b6cbb42b9f35a0f95f7c3bf29b8302970e"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2323"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.30"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-83c6-hcjv-pvmg"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Received",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-749"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Primary"
          }
        ]
      }
    }
  }
}



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