Systems running on s390x architecture could be made to crash or run programs as an administrator under certain conditions.
Al Viro discovered that the Linux kernel for s390x systems did not properly perform page table upgrades for kernel sections that use secondary address mode. A local attacker could use this to cause a denial of service (system crash) or execute arbitrary code.
28 April 2020
A security issue affects these releases of Ubuntu and its derivatives:
Systems running on s390x architecture could be made to crash or run programs as an administrator under certain conditions.
Al Viro discovered that the Linux kernel for s390x systems did not properly perform page table upgrades for kernel sections that use secondary address mode. A local attacker could use this to cause a denial of service (system crash) or execute arbitrary code.
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
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.
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