=========================================================================Ubuntu Security Notice USN-3816-1
November 12, 2018

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

- Ubuntu 18.10
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in systemd.

Software Description:
- systemd: system and service manager

Details:

Jann Horn discovered that unit_deserialize incorrectly handled status messages
above a certain length. A local attacker could potentially exploit this via
NotifyAccess to inject arbitrary state across re-execution and obtain root
privileges. (CVE-2018-15686)

Jann Horn discovered a race condition in chown_one(). A local attacker
could potentially exploit this by setting arbitrary permissions on certain
files to obtain root privileges. This issue only affected Ubuntu 18.04 LTS
and Ubuntu 18.10. (CVE-2018-15687)

It was discovered that systemd-tmpfiles mishandled symlinks in
non-terminal path components. A local attacker could potentially exploit
this by gaining ownership of certain files to obtain root privileges. This
issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2018-6954)

Update instructions:

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

Ubuntu 18.10:
  systemd                         239-7ubuntu10.3

Ubuntu 18.04 LTS:
  systemd                         237-3ubuntu10.6

Ubuntu 16.04 LTS:
  systemd                         229-4ubuntu21.8

After a standard system update you need to reboot your computer to make
all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-3816-1
  CVE-2018-15686, CVE-2018-15687, CVE-2018-6954

Package Information:
  https://launchpad.net/ubuntu/+source/systemd/239-7ubuntu10.3
  https://launchpad.net/ubuntu/+source/systemd/237-3ubuntu10.6
  https://launchpad.net/ubuntu/+source/systemd/229-4ubuntu21.8