The Apache Struts Team recommends to immediately upgrade your Struts 2.3.36 based projects to use the latest released version of Commons FileUpload library, which is currently 1.3.3. This is necessary to prevent your publicly accessible web site from being exposed to possible Remote Code Execution attacks (see  ).
This affects Struts 2.3.36 and prior. Struts versions from 2.5.12 are already using the latest commons-fileupload version . Your project is affected if it uses the built-in file upload mechanism of Struts 2, which defaults to the use of commons-fileupload. The updated commons-fileupload library is a drop-in replacement for the vulnerable version. Deployed applications can be hardened by replacing the commons-fileupload jar file in WEB-INF/lib with the fixed jar. For Maven based Struts 2 projects, the following dependency needs to be added: <dependency> <groupId>commons-fileupload</groupId> <artifactId>commons-fileupload</artifactId> <version>1.3.3</version> </dependency> More details can be found here:  https://issues.apache.org/jira/browse/FILEUPLOAD-279  https://nvd.nist.gov/vuln/detail/CVE-2016-1000031  https://issues.apache.org/jira/browse/WW-4812 All developers are strongly advised to perform this action. on behalf of the Apache Struts Team Kind regards -- Łukasz + 48 606 323 122 http://www.lenart.org.pl/