Use-after-free in libtransmission/variant.c in Transmission before 3.00 allows remote attackers to cause a denial of service (crash) or possibly execute arbitrary code via a crafted torrent file.
https://tomrichards.net/2020/05/cve-2018-10756-transmission/
https://security.gentoo.org/glsa/202007-07
https://lists.debian.org/debian-lts-announce/2020/08/msg00001.html
https://lists.debian.org/debian-lts-announce/2020/05/msg00022.html
https://github.com/transmission/transmission/commit/2123adf8e5e1c2b48791f9d22fc8c747e974180e