This indicates an attack attempt to exploit an Arbitrary File Upload vulnerability in Pixie File Manager.
The vulnerability is due to insufficient sanitizing of user supplied inputs when handling a crafted request. A remote attacker may be able to exploit this to upload a file with root privilege, which can lead to remote code execution as root.
Pixie 1.0.4 and earlier
System Compromise: Remote attackers can gain control of vulnerable systems.
Currently, we are unaware of any vendor supplied patch for this issue.