The virus detection engine in Sophos Anti-Virus before 2.49.0 does not properly process malformed (1) CAB, (2) LZH, and (3) RAR files with modified headers, which might allow remote attackers to bypass malware detection.
Sophos Anti-Virus before 4.02, 4.5.x before 4.5.9, 4.6.x before 4.6.9, and 5.x before 5.1.4 allow remote attackers to hide arbitrary files and data via crafted ARJ archives, which are not properly scanned.
Sophos Anti-Virus 3.78 allows remote attackers to bypass virus scanning by using a qmail generated Delivery Status Notification (DSN) where the original email is not included in the bounce message.