GuildFTPd 0.9.7 stores user names and passwords in plaintext in the default.usr file, which allows local users to gain privileges as other FTP users by reading the file.
https://exchange.xforce.ibmcloud.com/vulnerabilities/6611
http://www.securityfocus.com/bid/2792
http://archives.neohapsis.com/archives/bugtraq/2001-05/0250.html