USN-5240-1: Linux kernel vulnerability

19 January 2022

The system could be made to crash or run programs as an administrator.

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Details

William Liu and Jamie Hill-Daniel discovered that the file system context
functionality in the Linux kernel contained an integer underflow
vulnerability, leading to an out-of-bounds write. A local attacker could
use this to cause a denial of service (system crash) or execute arbitrary
code.

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Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

Learn more about Ubuntu Pro

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 21.10
Ubuntu 21.04
Ubuntu 20.04
Ubuntu 18.04

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

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