In BlueZ before 5.55, a double free was found in the gatttool disconnect_cb() routine from shared/att.c. A remote attacker could potentially cause a denial of service or code execution, during service discovery, due to a redundant disconnect MGMT event.
lists.opensuse.org/opensuse-security-announce/2020-11/msg00034.html
lists.opensuse.org/opensuse-security-announce/2020-11/msg00036.html
bugzilla.redhat.com/show_bug.cgi?id=1884817
github.com/bluez/bluez/commit/1cd644db8c23a2f530ddb93cebed7dacc5f5721a
github.com/bluez/bluez/commit/5a180f2ec9edfacafd95e5fed20d36fe8e077f07
lists.debian.org/debian-lts-announce/2020/10/msg00022.html
security.gentoo.org/glsa/202011-01
www.debian.org/security/2021/dsa-4951