🛡️ CVE-2026-34401 — xml-notepad

🟡 CVSS 6.5 — Medium ✅ No Known Exploit CWE-611 NVD
6.5
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. A user must be tricked into taking some action. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity none, availability none.

Weakness class

CVE-2026-34401 is classified as CWE-611: XML External Entity Reference (XXE). An XML parser resolves external entities, letting a crafted document read local files or reach internal services.

Affected software

CVE-2026-34401 is recorded against 1 package.

  • xml-notepad (fixed in 2.9.0.21)

Timeline and source

Published on 31 March 2026 and last revised on 24 July 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

github.com
github.com
github.com
github.com
github.com

Details

Severity MEDIUM
CVSS Score 6.5
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
CWE CWE-611
Public Exploit ✅ No
Source NVD
Published 2026-03-31
Updated 2026-08-11
Modified 2026-07-24

Affected Packages

Software From version Fixed in
xml-notepad 2.9.0.21

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