An attacker can manipulate file upload params to enable paths traversal and under some circumstances this can lead to uploading a malicious file which can be used to perform Remote Code Execution. Users are recommended to upgrade to versions Struts 2.5.33 or Struts 6.3.0.2 or greater to fix this issue.

File upload logic in Apache Struts is flawed. An attacker can manipulate file upload params to enable paths traversal and under some circumstances this can lead to uploading a malicious file which can be used to perform Remote Code Execution. This issue affects Apache Struts: from 2.0.0 before 6.4.0. Users are recommended to upgrade to version 6.4.0 at least and migrate to the new file upload mechanism https://struts.apache.org/core-developers/file-upload . If you are not using an old file upload logic based on FileuploadInterceptor your application is safe. You can find more details in  https://cwiki.apache.org/confluence/display/WW/S2-067

The Jakarta Multipart parser in Apache Struts 2 2.3.x before 2.3.32 and 2.5.x before 2.5.10.1 has incorrect exception handling and error-message generation during file-upload attempts, which allows remote attackers to execute arbitrary commands via a crafted Content-Type, Content-Disposition, or Content-Length HTTP header, as exploited in the wild in March 2017 with a Content-Type header containing a #cmd= string.

Forced OGNL evaluation, when evaluated on raw user input in tag attributes, may lead to remote code execution. Affected software : Apache Struts 2.0.0 - Struts 2.5.25.

Apache Struts 2.0.0 to 2.5.20 forced double OGNL evaluation, when evaluated on raw user input in tag attributes, may lead to remote code execution.

Apache Struts versions 2.3 to 2.3.34 and 2.5 to 2.5.16 suffer from possible Remote Code Execution when alwaysSelectFullNamespace is true (either by user or a plugin like Convention Plugin) and then: results are used with no namespace and in same time, its upper package have no or wildcard namespace and similar to results, same possibility when using url tag which doesn't have value and action set and in same time, its upper package have no or wildcard namespace.

When a Multipart request is performed but some of the fields exceed the maxStringLength  limit, the upload files will remain in struts.multipart.saveDir  even if the request has been denied. Users are recommended to upgrade to versions Struts 2.5.32 or 6.1.2.2 or Struts 6.3.0.1 or greater, which fixe this issue.

Allocation of Resources Without Limits or Throttling vulnerability in Apache Software Foundation Apache Struts.This issue affects Apache Struts: through 2.5.30, through 6.1.2. Upgrade to Struts 2.5.31 or 6.1.2.1 or greater

Allocation of Resources Without Limits or Throttling vulnerability in Apache Software Foundation Apache Struts.This issue affects Apache Struts: through 2.5.30, through 6.1.2. Upgrade to Struts 2.5.31 or 6.1.2.1 or greater.

The fix issued for CVE-2020-17530 was incomplete. So from Apache Struts 2.0.0 to 2.5.29, still some of the tag’s attributes could perform a double evaluation if a developer applied forced OGNL evaluation by using the %{...} syntax. Using forced OGNL evaluation on untrusted user input can lead to a Remote Code Execution and security degradation.