=========================================================================
Ubuntu Security Notice USN-5226-1
January 13, 2022

systemd vulnerability
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 21.10
- Ubuntu 21.04
- Ubuntu 20.04 LTS

Summary:

systemd-tmpfiles could be made to crash or have other unspecified impacts.

Software Description:
- systemd: system and service manager

Details:

It was discovered that systemd-tmpfiles employed uncontrolled recursion
when removing deeply nested directory hierarchies. A local attacker could
exploit this to cause systemd-tmpfiles to crash or have other unspecified
impacts.

Update instructions:

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

Ubuntu 21.10:
  systemd                         248.3-1ubuntu8.2

Ubuntu 21.04:
  systemd                         247.3-3ubuntu3.7

Ubuntu 20.04 LTS:
  systemd                         245.4-4ubuntu3.15

In general, a standard system update will make all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-5226-1
  CVE-2021-3997

Package Information:
  https://launchpad.net/ubuntu/+source/systemd/248.3-1ubuntu8.2
  https://launchpad.net/ubuntu/+source/systemd/247.3-3ubuntu3.7
  https://launchpad.net/ubuntu/+source/systemd/245.4-4ubuntu3.15