net-ftp/netkit-ftpd is the Linux Netkit FTP server with optional SSL support.
Venustech AD-LAB discovered that an FTP client connected to a vulnerable server with passive mode and SSL support can trigger an fclose() function call on an uninitialized stream in ftpd.c.
A remote attacker can send specially crafted FTP data to a server with passive mode and SSL support, causing the ftpd daemon to crash.
Disable passive mode or SSL.
All Netkit FTP Server users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-ftp/netkit-ftpd-0.17-r7"