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.
https://exchange.xforce.ibmcloud.com/vulnerabilities/17761
http://www.kb.cert.org/vuls/id/968818
http://www.idefense.com/application/poi/display?id=153&type=vulnerabilities&flashstatus=true