CVE-2026-34401
Last modified
CVE-2026-34401 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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. EPSS estimates a 0.99% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Xml Notepad | < 2.9.0.21 |
References
- https://github.com/microsoft/XmlNotepad/releases/tag/2.9.0.21Product, Release Notes
- https://github.com/microsoft/XmlNotepad/security/advisories/GHSA-5j32-486h-42chMitigation, Vendor Advisory
- https://github.com/microsoft/XmlNotepad/security/advisories/GHSA-5j32-486h-42chMitigation, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
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