Ubuntu Security Notice 5469-1 - 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. 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 or execute arbitrary code. Continue reading...
