It was determined that your web application is performing Python object deserialization (using the pickle library) of user-supplied data. Arbitrary object deserialization is inherently unsafe, and should never be performed on untrusted data. Consult Web references section for more information about this issue.
The pickle module is not intended to be secure against erroneous or maliciously constructed data. Never unpickle data received from an untrusted or unauthenticated source.