Summary
Incomplete Cleanup vulnerability in Apache Tomcat.
The internal fork of Commons FileUpload packaged with Apache Tomcat 9.0.70 through 9.0.80 and 8.5.85 through 8.5.93 included an unreleased, in progress refactoring that exposed a potential denial of service on Windows if a web application opened a stream for an uploaded file but failed to close the stream. The file would never be deleted from disk creating the possibility of an eventual denial of service due to the disk being full.
Users are recommended to upgrade to version 9.0.81 onwards or 8.5.94 onwards, which fixes the issue.
Impact
CVE-2023-42794 has a CVSS score of 5.9 (Medium). 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 (9.0.81, 8.5.94); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
org.apache.tomcat:tomcat-coyote to 9.0.81 or later; org.apache.tomcat:tomcat-coyote to 8.5.94 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2023-42794? CVE-2023-42794 is a medium-severity security vulnerability in org.apache.tomcat:tomcat-coyote (maven), affecting versions >= 9.0.70, < 9.0.81. It is fixed in 9.0.81, 8.5.94.
- How severe is CVE-2023-42794? CVE-2023-42794 has a CVSS score of 5.9 (Medium). 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.
- Which versions of org.apache.tomcat:tomcat-coyote are affected by CVE-2023-42794? org.apache.tomcat:tomcat-coyote (maven) versions >= 9.0.70, < 9.0.81 is affected.
- Is there a fix for CVE-2023-42794? Yes. CVE-2023-42794 is fixed in 9.0.81, 8.5.94. Upgrade to this version or later.
- Is CVE-2023-42794 exploitable, and should I be worried? Whether CVE-2023-42794 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
- What actually determines whether CVE-2023-42794 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.
- How do I fix CVE-2023-42794?
- Upgrade
org.apache.tomcat:tomcat-coyoteto 9.0.81 or later - Upgrade
org.apache.tomcat:tomcat-coyoteto 8.5.94 or later
- Upgrade