A proftpd-dfsg security update has been released for Debian GNU/Linux 8 LTS to fix an issue in mod_tls

Package : proftpd-dfsg
Version : 1.3.5e+r1.3.5-2+deb8u5
CVE ID : CVE-2019-19269

In mod_tls a crash with empty CRL was fixed.

For Debian 8 "Jessie", this problem has been fixed in version
1.3.5e+r1.3.5-2+deb8u5.

We recommend that you upgrade your proftpd-dfsg packages.

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS