Heap-based buffer overflow in the SIS unpacker in avast! Anti-Virus Managed Client before 4.7.700 allows user-assisted remote attackers to execute arbitrary code via a crafted SIS archive, resulting from an "integer cast around."

Race condition in avast! Internet Security 5.0.462 on Windows XP allows local users to bypass kernel-mode hook handlers, and execute dangerous code that would otherwise be blocked by a handler but not blocked by signature-based malware detection, via certain user-space memory changes during hook-handler execution, aka an argument-switch attack or a KHOBE attack. NOTE: this issue is disputed by some third parties because it is a flaw in a protection mechanism for situations where a crafted program has already begun to execute