CVEvulnerability
CVE-2026-34401
6.5 MEDIUM
Official page ↗
- Status
- Analyzed
- Published
- 2026-03-31
- Last modified
- 2026-07-24
- Assigner
- [email protected]
- CVSS 3.1 ([email protected])
- 6.5 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
- Weaknesses
- CWE-611
Description
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.
Affected configurations
• microsoft xml notepad (< 2.9.0.21)
Related
Weakness · CWE (1)
- CWE-611 Improper Restriction of XML External Entity Reference weakness
References
- https://github.com/microsoft/XmlNotepad/commit/3665603d61ba10b7827a3724e854748cb780140c Patch
- https://github.com/microsoft/XmlNotepad/commit/c03ab2311ac6960452eb1ab49098768f851dcc53 Patch
- https://github.com/microsoft/XmlNotepad/releases/tag/2.9.0.21 Product, Release Notes
- https://github.com/microsoft/XmlNotepad/security/advisories/GHSA-5j32-486h-42ch Mitigation, Vendor Advisory
- https://github.com/microsoft/XmlNotepad/security/advisories/GHSA-5j32-486h-42ch Mitigation, Vendor Advisory