Sophos Anti-Virus 5.0.1, with "Scan inside archive files" enabled, allows remote attackers to cause a denial of service (CPU consumption by infinite loop) via a Bzip2 archive with a large 'Extra field length' value.

Sophos Anti-Virus 3.93 does not check downloaded files for viruses when they have only been written, which creates a race condition and may allow remote attackers to bypass virus protection if the file is executed before the antivirus starts on system reboot.

Sophos Anti-Virus before 3.87.0, and Sophos Anti-Virus for Windows 95, 98, and Me before 3.88.0, allows remote attackers to bypass antivirus protection via a compressed file with both local and global headers set to zero, which does not prevent the compressed file from being opened on a target system.

Sophos Anti-Virus 3.78 allows remote attackers to cause a denial of service (infinite loop) via a MIME header that is not properly terminated.

Sophos Small Business Suite 1.00 on Windows does not properly handle files whose names contain reserved MS-DOS device names such as (1) LPT1, (2) COM1, (3) AUX, (4) CON, or (5) PRN, which can allow malicious code to bypass detection when it is installed, copied, or executed.

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.