bluez vulnerabilities

USN-4989-1 fixed several vulnerabilities in BlueZ. This update provides
the corresponding update for Ubuntu 16.04 ESM.

Original advisory details:

It was discovered that BlueZ incorrectly checked certain permissions when
pairing. A local attacker could possibly use this issue to impersonate
devices. (CVE-2020-26558)

Jay LV discovered that BlueZ incorrectly handled redundant disconnect MGMT
events. A local attacker could use this issue to cause BlueZ to crash,
resulting in a denial of service, or possibly execute arbitrary code. This
issue only affected Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2020-27153)