This indicates an attack attempt to exploit a Buffer Overflow vulnerability in Info-ZIP UnZip.
The vulnerability is due to insufficient checking of user supplied data when the vulnerable software handles a maliciously crafted ZIP file. An attacker can exploit this by tricking an unsuspecting user into opening a malicious file and execute arbitrary code within the context of the application.
Info-ZIP UnZip 6.0 and prior
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.