This indicates an attack attempt against a Command Execution vulnerability in Blender.
The vulnerability is caused by an error when the vulnerable software handles a malicious .blend file. It allows a remote attacker to execute arbitrary command via sending a crafted .blend file.
Blender Blender 2.49b and prior
System Compromise: Remote attackers can gain control of vulnerable systems.
Currently we are not aware of any vendor supplied patch for this issue.