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CVE-2021-23639

Status: ModifiedCritical (9.8)—💥 PoC

The package md-to-pdf before 5.0.0 are vulnerable to Remote Code Execution (RCE) due to utilizing the library gray-matter to parse front matter content, without disabling the JS engine.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

💥 Public exploits

Exploit code or detection templates are publicly available. This is not the same as confirmed active exploitation (KEV), but it raises the risk: patch with priority.

⚠️ GitHub proofs of concept are not verified: some are fake or contain malware. Never run them outside an isolated lab.

Affected technologies (1)

Markdown TO PDF Project — Markdown TO PDF

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2021-23639",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 7.5,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:P/I:P/A:P",
          "authentication": "NONE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "LOW",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": false,
        "impactScore": 6.4,
        "baseSeverity": "HIGH",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 10,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "report@snyk.io",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      },
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
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          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "report@snyk.io",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "md-to-pdf",
          "versions": [
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              "status": "affected",
              "version": "unspecified",
              "lessThan": "5.0.0",
              "versionType": "custom"
            }
          ]
        }
      ]
    }
  ],
  "published": "2021-12-10T20:15:08.387",
  "references": [
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      "url": "https://github.com/simonhaenisch/md-to-pdf/commit/a716259c548c82fa1d3b14a3422e9100619d2d8a",
      "tags": [
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        "Third Party Advisory"
      ],
      "source": "report@snyk.io"
    },
    {
      "url": "https://github.com/simonhaenisch/md-to-pdf/issues/99",
      "tags": [
        "Exploit",
        "Issue Tracking",
        "Patch",
        "Third Party Advisory"
      ],
      "source": "report@snyk.io"
    },
    {
      "url": "https://snyk.io/vuln/SNYK-JS-MDTOPDF-1657880",
      "tags": [
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        "Patch",
        "Third Party Advisory"
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      "source": "report@snyk.io"
    },
    {
      "url": "https://github.com/simonhaenisch/md-to-pdf/commit/a716259c548c82fa1d3b14a3422e9100619d2d8a",
      "tags": [
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        "Third Party Advisory"
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://github.com/simonhaenisch/md-to-pdf/issues/99",
      "tags": [
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        "Issue Tracking",
        "Patch",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://snyk.io/vuln/SNYK-JS-MDTOPDF-1657880",
      "tags": [
        "Exploit",
        "Patch",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "The package md-to-pdf before 5.0.0 are vulnerable to Remote Code Execution (RCE) due to utilizing the library gray-matter to parse front matter content, without disabling the JS engine."
    },
    {
      "lang": "es",
      "value": "El paquete md-to-pdf versiones anteriores a 5.0.0, es vulnerable a una Ejecución de Código Remota (RCE) debido al uso de la biblioteca gray-matter para analizar el contenido del front matter, sin deshabilitar el motor JS"
    }
  ],
  "lastModified": "2026-06-17T03:38:50.977",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:markdown_to_pdf_project:markdown_to_pdf:*:*:*:*:*:node.js:*:*",
              "vulnerable": true,
              "matchCriteriaId": "3FF5044C-A0C6-4CF9-AB44-E51BF070AF85",
              "versionEndExcluding": "5.0.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "report@snyk.io"
}