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
| Link | Resource |
|---|---|
| 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 |
Configurations
History
13 Apr 2026, 15:19
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:a:microsoft:xml_notepad:*:*:*:*:*:windows:*:* | |
| References | () https://github.com/microsoft/XmlNotepad/commit/3665603d61ba10b7827a3724e854748cb780140c - Patch | |
| References | () https://github.com/microsoft/XmlNotepad/commit/c03ab2311ac6960452eb1ab49098768f851dcc53 - Patch | |
| References | () https://github.com/microsoft/XmlNotepad/releases/tag/2.9.0.21 - Product, Release Notes | |
| References | () https://github.com/microsoft/XmlNotepad/security/advisories/GHSA-5j32-486h-42ch - Mitigation, Vendor Advisory | |
| First Time |
Microsoft xml Notepad
Microsoft |
01 Apr 2026, 17:28
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://github.com/microsoft/XmlNotepad/security/advisories/GHSA-5j32-486h-42ch - |
31 Mar 2026, 22:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-03-31 22:16
Updated : 2026-04-13 15:19
NVD link : CVE-2026-34401
Mitre link : CVE-2026-34401
CVE.ORG link : CVE-2026-34401
JSON object : View
Products Affected
microsoft
- xml_notepad
CWE
CWE-611
Improper Restriction of XML External Entity Reference
