IPFilter 3.1.1 through 3.4.28 allows remote attackers to bypass firewall rules by sending a PASV command string as the argument of another command to an FTP server, which generates a response that contains the string, causing IPFilter to treat the response as if it were a legitimate PASV command from the server.
Race condition in IPFilter firewall 3.4.3 and earlier, when configured with overlapping "return-rst" and "keep state" rules, allows remote attackers to bypass access restrictions.