This indicates an attack attempt to exploit a Buffer Overflow vulnerability in Libmspack Project libmspack library.
The vulnerability is a result of an improper handling of block alignment when processing CAB files, leading to an off by one byte error. It may allow a remote attacker to execute arbitrary code within the context of the application.
Libmspack Project libmspack prior to 0.8 alpha
Products using the vulnerable library, including:
Libmspack Project cabextract prior to 1.8
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply patch available from the vendor: