CVE-2023-42794 — tomcat-coyote
MEDIUMCVE-2023-42794 is a medium-severity (CVSS 5.9) CWE-459 vulnerability in org.apache.tomcat:tomcat-coyote. A fix is available for org.apache.tomcat:tomcat-coyote — see the affected versions and patch details below.
Apache Tomcat: FileUpload: DoS due to accumulation of temporary files on Windows
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
org.apache.tomcat:tomcat-coyote☕org.apache.tomcat:tomcat-coyoteReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
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.
Other, EOL versions may also be affected.
Users are recommended to upgrade to version 9.0.81 onwards or 8.5.94 onwards, which fixes the issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.tomcat:tomcat-coyote | ≥ 9.0.70&&< 9.0.81 | 9.0.81org.apache.tomcat:tomcat-coyote:9.0.81 |
| ☕Maven | org.apache.tomcat:tomcat-coyote | ≥ 8.5.85&&< 8.5.94 | 8.5.94org.apache.tomcat:tomcat-coyote:8.5.94 |
Affected Products
tomcatapacheDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.tomcat:tomcat-coyote, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.tomcat:tomcat-coyote to 9.0.81 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-42794 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Red Hat rates this flaw as a Moderate impact as this would depend on how much information an attacker has over the environment (version and disk for example, increasing the Attack Complexity) as there is no guarantee the attack is successful. This may affect only scenarios where running an application on Windows.
No mitigation is currently available for this flaw.Source: Red Hat security advisory for CVE-2023-42794 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 8 | tomcat-1:9.0.62-27.el8_9.2 | RHSA-2024:0125 |
| Red Hat Enterprise Linux 9 | tomcat-1:9.0.62-37.el9_3.1 | RHSA-2024:0474 |
| Red Hat Fuse 7.12.1 | tomcat | RHSA-2023:7247 |
| Red Hat JBoss Web Server 5 | see advisory | RHSA-2023:7623 |
Frequently Asked Questions
Is CVE-2023-42794 in your dependencies?
Find it across Maven, including transitive dependencies.