bftpd Configuration File options.c expand_groups heap-based overflow

A weakness has been identified in bftpd up to 6.2. Impacted is the function expand_groups of the file options.c of the component Configuration File Handler. Executing a manipulation can lead to heap-based buffer overflow. It is possible to launch the attack on the local host. Attacks of this nature are highly complex. The exploitability is considered difficult. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.