USN-5484-1: 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) It was discovered that a race condition existed in the network scheduling 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-2021-39713) It was discovered that some Intel processors did not completely perform cleanup actions on multi-core shared buffers. A local attacker could possibly use this to expose sensitive information. (CVE-2022-21123) It was discovered that some Intel processors did not completely perform cleanup actions on microarchitectural fill buffers. A local attacker could possibly use this to expose sensitive information. (CVE-2022-21125) It was discovered that some Intel processors did not properly perform cleanup during specific special register write operations. A local attacker could possibly use this to expose sensitive information. (CVE-2022-21166)