CVE-2023-26048

Workarounds

Multipart parameter maxRequestSize must be set to a non-negative value, so the whole multipart content is limited (although still read into memory).
Limiting multipart parameter maxFileSize won't be enough because an attacker can send a large number of parts that summed up will cause memory issues.

References

• https://github.com/eclipse/jetty.project/issues/9076
• https://github.com/jakartaee/servlet/blob/6.0.0/spec/src/main/asciidoc/servlet-spec-body.adoc#32-file-upload

Servlets with multipart support (e.g. annotated with @MultipartConfig) that call HttpServletRequest.getParameter() or HttpServletRequest.getParts() may cause OutOfMemoryError when the client sends a multipart request with a part that has a name but no filename and a very large content.

This happens even with the default settings of fileSizeThreshold=0 which should stream the whole part content to disk.

An attacker client may send a large multipart request and cause the server to throw OutOfMemoryError.
However, the server may be able to recover after the OutOfMemoryError and continue its service -- although it may take some time.

A very large number of parts may cause the same problem.

Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.

CVE-2023-26048 has a CVSS score of 5.3 (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 (10.0.14, 11.0.14, 9.4.51.v20230217); upgrading removes the vulnerable code path.

Kodem intelligence

Patched in Jetty versions

• 9.4.51.v20230217 - via PR #9345
• 10.0.14 - via PR #9344
• 11.0.14 - via PR #9344

1. What is CVE-2023-26048? CVE-2023-26048 is a medium-severity uncontrolled resource consumption vulnerability in org.eclipse.jetty:jetty-server (maven), affecting versions >= 10.0.0, < 10.0.14. It is fixed in 10.0.14, 11.0.14, 9.4.51.v20230217. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
2. How severe is CVE-2023-26048? CVE-2023-26048 has a CVSS score of 5.3 (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.
3. Which versions of org.eclipse.jetty:jetty-server are affected by CVE-2023-26048? org.eclipse.jetty:jetty-server (maven) versions >= 10.0.0, < 10.0.14 is affected.
4. Is there a fix for CVE-2023-26048? Yes. CVE-2023-26048 is fixed in 10.0.14, 11.0.14, 9.4.51.v20230217. Upgrade to this version or later.
5. Is CVE-2023-26048 exploitable, and should I be worried? Whether CVE-2023-26048 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-2023-26048 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-2023-26048?
   • Upgrade org.eclipse.jetty:jetty-server to 10.0.14 or later
   • Upgrade org.eclipse.jetty:jetty-server to 11.0.14 or later
   • Upgrade org.eclipse.jetty:jetty-server to 9.4.51.v20230217 or later