CVE-2025-52520

For some unlikely configurations of multipart upload, an Integer Overflow vulnerability in Apache Tomcat could lead to a DoS via bypassing of size limits.

This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.8, from 10.1.0-M1 through 10.1.42, from 9.0.0.M1 through 9.0.106. The following versions were EOL at the time the CVE was created but are known to be affected: 8.5.0 through 8.5.100. Other, older, EOL versions may also be affected.

Users are recommended to upgrade to version 11.0.9, 10.1.43 or 9.0.107, which fix the issue.

An arithmetic operation produces a value that exceeds the integer type's maximum, causing it to wrap to an unexpected small value. Typical impact: incorrect size calculations leading to heap overflows or logic errors.

CVE-2025-52520 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 (11.0.9, 10.1.43, 9.0.107); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-52520? CVE-2025-52520 is a high-severity integer overflow or wraparound vulnerability in org.apache.tomcat:tomcat-catalina (maven), affecting versions >= 11.0.0-M1, < 11.0.9. It is fixed in 11.0.9, 10.1.43, 9.0.107. An arithmetic operation produces a value that exceeds the integer type's maximum, causing it to wrap to an unexpected small value.
2. How severe is CVE-2025-52520? CVE-2025-52520 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-2025-52520?
   • org.apache.tomcat:tomcat-catalina (maven) (versions >= 11.0.0-M1, < 11.0.9)
   • org.apache.tomcat.embed:tomcat-embed-core (maven) (versions >= 11.0.0-M1, < 11.0.9)
4. Is there a fix for CVE-2025-52520? Yes. CVE-2025-52520 is fixed in 11.0.9, 10.1.43, 9.0.107. Upgrade to this version or later.
5. Is CVE-2025-52520 exploitable, and should I be worried? Whether CVE-2025-52520 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-2025-52520 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-2025-52520?
   • Upgrade org.apache.tomcat:tomcat-catalina to 11.0.9 or later
   • Upgrade org.apache.tomcat:tomcat-catalina to 10.1.43 or later
   • Upgrade org.apache.tomcat:tomcat-catalina to 9.0.107 or later
   • Upgrade org.apache.tomcat.embed:tomcat-embed-core to 11.0.9 or later
   • Upgrade org.apache.tomcat.embed:tomcat-embed-core to 10.1.43 or later
   • Upgrade org.apache.tomcat.embed:tomcat-embed-core to 9.0.107 or later