CVE-2026-61570

MPXJ: XXE Vulnerability in MerlinReader

Workarounds

Potential workarounds include:

• Avoid reading Merlin project files with MPXJ
• Only accept Merlin project files from trusted sources
• Preprocess Merlin SQLite databases to strip doctype declarations from the ZTIMEINTERVALS column

MPXJ used the default configuration when creating a DocumentBuilder instance, which leaves doctype declarations enabled, when parsing the XML content of the ZTIMEINTERVALS column from a Merlin project SQLite file. This would allow a carefully crafted XML payload to read an arbitrary file. However, although an arbitrary file can be read, the way the resulting parsed XML is processed by MPXJ means that the data it contains is unlikely to be available for exfiltration.

An XML parser processes external entity references in untrusted input, causing the server to fetch internal resources or remote URLs. Typical impact: local file disclosure, server-side request forgery, or denial of service.

CVE-2026-61570 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (16.4.1); upgrading removes the vulnerable code path.

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The patch is included in MPXJ 16.4.1

1. What is CVE-2026-61570? CVE-2026-61570 is a high-severity XML external entity injection (XXE) vulnerability in net.sf.mpxj:mpxj (maven), affecting versions >= 5.5.5, < 16.4.1. It is fixed in 16.4.1. An XML parser processes external entity references in untrusted input, causing the server to fetch internal resources or remote URLs.
2. How severe is CVE-2026-61570? CVE-2026-61570 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2026-61570?
   • net.sf.mpxj:mpxj (maven) (versions >= 5.5.5, < 16.4.1)
   • mpxj (rubygems) (versions >= 5.5.5, < 16.4.1)
   • MPXJ.Net (nuget) (versions >= 5.5.5, < 16.4.1)
   • net.sf.mpxj (nuget) (versions >= 5.5.5, < 16.4.1)
   • net.sf.mpxj-for-csharp (nuget) (versions >= 5.5.5, < 16.4.1)
   • net.sf.mpxj-for-vb (nuget) (versions >= 5.5.5, < 16.4.1)
4. Is there a fix for CVE-2026-61570? Yes. CVE-2026-61570 is fixed in 16.4.1. Upgrade to this version or later.
5. Is CVE-2026-61570 exploitable, and should I be worried? Whether CVE-2026-61570 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-61570 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-61570?
   • Upgrade net.sf.mpxj:mpxj to 16.4.1 or later
   • Upgrade mpxj to 16.4.1 or later
   • Upgrade MPXJ.Net to 16.4.1 or later
   • Upgrade net.sf.mpxj to 16.4.1 or later
   • Upgrade net.sf.mpxj-for-csharp to 16.4.1 or later
   • Upgrade net.sf.mpxj-for-vb to 16.4.1 or later
   • Upgrade mpxj to 16.4.1 or later

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