Apache Struts 2.3.x before 2.3.32 and 2.5.x before 2.5.10.1 is susceptible to remote command injection attacks. The Jakarta Multipart parser has incorrect exception handling and error-message generation during file upload attempts, which can allow an attacker to execute arbitrary commands via a crafted Content-Type, Content-Disposition, or Content-Length HTTP header. This was exploited in March 2017 with a Content-Type header containing a#cmd= string.