Several security issues were fixed in the Linux kernel.
Likang Luo discovered that a race condition existed in the Bluetooth subsystem of the Linux kernel, leading to a use-after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-3752) ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well.
Keyu Man discovered that the ICMP implementation in the Linux kernel did
not properly handle received ICMP error packets. A remote attacker could
use this to facilitate attacks on UDP based services that depend on source
port randomization. (CVE-2021-20322)
It was discovered that the Bluetooth subsystem in the Linux kernel
contained a use-after-free vulnerability. A local attacker could use this
to cause a denial of service (system crash) or possibly execute arbitrary
code. (CVE-2021-3640)
Likang Luo discovered that a race condition existed in the Bluetooth
subsystem of the Linux kernel, leading to a use-after-free vulnerability. A
local attacker could use this to cause a denial of service (system crash)
or possibly execute arbitrary code. (CVE-2021-3752)
Luo Likang discovered that the FireDTV Firewire driver in the Linux kernel
did not properly perform bounds checking in some situations. A local
attacker could use this to cause a denial of service (system crash) or
possibly execute arbitrary code. (CVE-2021-42739)