Ubuntu Security Notice 5484-1 - 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. 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 or possibly execute arbitrary code.
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