Multiple interpretation error in various F-Secure Anti-Virus products, including Workstation 5.43 and earlier, Windows Servers 5.50 and earlier, MIMEsweeper 5.50 and earlier, Anti-Virus for Linux Servers and Gateways 4.61 and earlier, and other products, 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 the target system.