A bug with security implications was found in the mod_tls module in ProFTPD before 1.3.5b. This module has a configuration option TLSDHParamFile to specify user-defined Diffie Hellman parameters. The software would ignore the user-defined parameters and use Diffie Hellman key exchanges with 1024 bits (CVE-2016-3125).
The proftpd package has been updated to version 1.3.5b, which fixes this issue and other bugs, including: - SSH RSA hostkeys smaller than 2048 bits now work properly. - MLSD response lines are now properly CRLF terminated.