Debian stable repositories currently serve version 4.13.13.
Multiple security releases have been issued by samba since then: from 4.13.14 to the recent 4.13.17 which fixes CVE-2021-44142 [1].<p>It seems the current maintainer does not have any more time to work on the package [2].<p>[1] <a href="https://www.samba.org/samba/history/security.html" rel="nofollow">https://www.samba.org/samba/history/security.html</a><p>[2] <a href="https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=814382" rel="nofollow">https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=814382</a>