CVE-2026-34401 (GCVE-0-2026-34401)

Vulnerability from cvelistv5 – Published: 2026-03-31 21:05 – Updated: 2026-04-01 15:53
VLAI
Title
XML Notepad: XML External Entity (XXE) Injection via Unsafe XmlTextReader in XML Diff and Schema Loading
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.
Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
SSVC
Exploitation: poc Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-04-01 15:45 UTC
CWE
  • CWE-611 - Improper Restriction of XML External Entity Reference
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7993 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
microsoft XmlNotepad Affected: < 2.9.0.21
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

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