FKIE_CVE-2026-34401

Vulnerability from fkie_nvd - Published: 2026-03-31 22:16 - Updated: 2026-04-01 17:28
Severity ?
6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Summary
XML Notepad is a Windows program that provides a simple intuitive User Interface for browsing and editing XML documents. Prior to version 2.9.0.21, XML Notepad does not disable DTD processing by default which means external entities are resolved automatically. There is a well known attack related to malicious DTD files where an attacker to craft a malicious XML file that loads a DTD that causes XML Notepad to make outbound HTTP/SMB requests, potentially leaking local file contents or capturing the victim's NTLM credentials. This issue has been patched in version 2.9.0.21.
References
security-advisories@github.comhttps://github.com/microsoft/XmlNotepad/commit/3665603d61ba10b7827a3724e854748cb780140c
security-advisories@github.comhttps://github.com/microsoft/XmlNotepad/commit/c03ab2311ac6960452eb1ab49098768f851dcc53
security-advisories@github.comhttps://github.com/microsoft/XmlNotepad/releases/tag/2.9.0.21
security-advisories@github.comhttps://github.com/microsoft/XmlNotepad/security/advisories/GHSA-5j32-486h-42ch
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/microsoft/XmlNotepad/security/advisories/GHSA-5j32-486h-42ch
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "XML Notepad is a Windows program that provides a simple intuitive User Interface for browsing and editing XML documents. Prior to version 2.9.0.21, XML Notepad does not disable DTD processing by default which means external entities are resolved automatically. There is a well known attack related to malicious DTD files where an attacker to craft a malicious XML file that loads a DTD that causes XML Notepad to make outbound HTTP/SMB requests, potentially leaking local file contents or capturing the victim\u0027s NTLM credentials. This issue has been patched in version 2.9.0.21."
    }
  ],
  "id": "CVE-2026-34401",
  "lastModified": "2026-04-01T17:28:40.303",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-03-31T22:16:18.490",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/microsoft/XmlNotepad/commit/3665603d61ba10b7827a3724e854748cb780140c"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/microsoft/XmlNotepad/commit/c03ab2311ac6960452eb1ab49098768f851dcc53"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/microsoft/XmlNotepad/releases/tag/2.9.0.21"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/microsoft/XmlNotepad/security/advisories/GHSA-5j32-486h-42ch"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/microsoft/XmlNotepad/security/advisories/GHSA-5j32-486h-42ch"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-611"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}


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