USN-5465-1: Linux kernel vulnerabilities

It was discovered that the Linux kernel did not properly restrict access to the kernel debugger when booted in secure boot environments. A privileged attacker could use this to bypass UEFI Secure Boot restrictions. (CVE-2022-21499) Aaron Adams discovered that the netfilter subsystem in the Linux kernel did not properly handle the removal of stateful expressions in some situations, leading to a use-after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or execute arbitrary code. (CVE-2022-1966) Jann Horn discovered that the Linux kernel did not properly enforce seccomp restrictions in some situations. A local attacker could use this to bypass intended seccomp sandbox restrictions. (CVE-2022-30594)