This indicates an attack attempt to exploit a Denial of Service vulnerability in Apache Tomcat.
The vulnerability is due to an boundary check error when handling a Content-Type header of a multipart HTTP request. A remote attacker may be able to exploit this to cause a denial of service condition on the affected system.
Apache Software Foundation Commons FileUpload prior to 1.3.2
Apache Tomcat prior to 9.0.0M8
Apache Tomcat prior to 8.0.36
Apache Tomcat prior to 7.0.70
Denial of Service: Remote attackers can crash vulnerable systems or services
Apply the most recent upgrade or patch from the vendor