Several security issues were fixed in the Linux kernel.
Jann Horn discovered that the userfaultd implementation in the Linux kernel did not properly restrict access to certain ioctls. A local attacker could use this possibly to modify files. (CVE-2018-18397)
5 March 2019
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in the Linux kernel.
Jann Horn discovered that the userfaultd implementation in the Linux kernel did not properly restrict access to certain ioctls. A local attacker could use this possibly to modify files. (CVE-2018-18397)
It was discovered that the crypto subsystem of the Linux kernel leaked uninitialized memory to user space in some situations. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2018-19854)
Jann Horn discovered a race condition in the fork() system call in the Linux kernel. A local attacker could use this to gain access to services that cache authorizations. (CVE-2019-6133)
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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