[USN-5211-1] Linux kernel vulnerability

========================================================================== Ubuntu Security Notice USN-5211-1 January 06, 2022
linux, linux-aws, linux-kvm, linux-lts-xenial vulnerability ==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
– Ubuntu 16.04 ESM – Ubuntu 14.04 ESM
Summary:
The system could be made to crash or run programs as an administrator.
Software Description: – linux: Linux kernel – linux-aws: Linux kernel for Amazon Web Services (AWS) systems – linux-kvm: Linux kernel for cloud environments – linux-lts-xenial: Linux hardware enablement kernel from Xenial for Trusty
Details:
Nadav Amit discovered that the hugetlb implementation in the Linux kernel did not perform TLB flushes under certain conditions. A local attacker could use this to leak or alter data from other processes that use huge pages.
Update instructions:
The problem can be corrected by updating your system to the following package versions:
Ubuntu 16.04 ESM: linux-image-4.4.0-1099-kvm 4.4.0-1099.108 linux-image-4.4.0-1134-aws 4.4.0-1134.148 linux-image-4.4.0-218-generic 4.4.0-218.251 linux-image-4.4.0-218-lowlatency 4.4.0-218.251 linux-image-aws 4.4.0.1134.139 linux-image-generic 4.4.0.218.225 linux-image-kvm 4.4.0.1099.97 linux-image-lowlatency 4.4.0.218.225 linux-image-virtual 4.4.0.218.225
Ubuntu 14.04 ESM: linux-image-3.13.0-189-generic 3.13.0-189.240 linux-image-3.13.0-189-generic-lpae 3.13.0-189.240 linux-image-3.13.0-189-lowlatency 3.13.0-189.240 linux-image-4.4.0-1098-aws 4.4.0-1098.103 linux-image-4.4.0-218-generic 4.4.0-218.251~14.04.1 linux-image-4.4.0-218-lowlatency 4.4.0-218.251~14.04.1 linux-image-aws 4.4.0.1098.96 linux-image-generic 3.13.0.189.198 linux-image-generic-lpae 3.13.0.189.198 linux-image-generic-lts-xenial 4.4.0.218.189 linux-image-lowlatency 3.13.0.189.198 linux-image-lowlatency-lts-xenial 4.4.0.218.189 linux-image-server 3.13.0.189.198 linux-image-virtual 3.13.0.189.198 linux-image-virtual-lts-xenial 4.4.0.218.189
After a standard system update you need to reboot your computer to make all the necessary changes.
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.
References: ubuntu.com/security/notices/USN-5211-1 CVE-2021-4002