The following updates has been released for Ubuntu Linux:

USN-3736-1: libarchive vulnerabilities
USN-3737-1: GDM vulnerability

USN-3736-1: libarchive vulnerabilities

==========================================================================
Ubuntu Security Notice USN-3736-1
August 13, 2018

libarchive vulnerabilities
==========================================================================

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

- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

Several security issues were fixed in libarchive.

Software Description:
- libarchive: Library to read/write archive files

Details:

It was discovered that libarchive incorrectly handled certain archive
files. A remote attacker could possibly use this issue to cause a
denial of service. This issue only affected Ubuntu 14.04 LTS and Ubuntu
16.04 LTS. (CVE-2016-10209, CVE-2016-10349, CVE-2016-10350)

Agostino Sarubbo discovered that libarchive incorrectly handled certain
XAR files. A remote attacker could possibly use this issue to cause a
denial of service. This issue only affected Ubuntu 14.04 LTS and Ubuntu
16.04 LTS. (CVE-2017-14166)

It was discovered that libarchive incorrectly handled certain files.
A remote attacker could possibly use this issue to get access to
sensitive information. (CVE-2017-14501, CVE-2017-14503)

Update instructions:

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

Ubuntu 18.04 LTS:
  libarchive13 3.2.2-3.1ubuntu0.1

Ubuntu 16.04 LTS:
  libarchive13 3.1.2-11ubuntu0.16.04.4

Ubuntu 14.04 LTS:
  libarchive13 3.1.2-7ubuntu2.6

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

References:
  https://usn.ubuntu.com/usn/usn-3736-1
  CVE-2016-10209, CVE-2016-10349, CVE-2016-10350, CVE-2017-14166,
  CVE-2017-14501, CVE-2017-14503

Package Information:
  https://launchpad.net/ubuntu/+source/libarchive/3.2.2-3.1ubuntu0.1
  https://launchpad.net/ubuntu/+source/libarchive/3.1.2-11ubuntu0.16.04.4
  https://launchpad.net/ubuntu/+source/libarchive/3.1.2-7ubuntu2.6

USN-3737-1: GDM vulnerability

==========================================================================
Ubuntu Security Notice USN-3737-1
August 13, 2018

gdm3 vulnerability
==========================================================================

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

- Ubuntu 18.04 LTS

Summary:

GDM could be made to crash or run programs as the administrator.

Software Description:
- gdm3: GNOME Display Manager

Details:

A use-after-free was discovered in GDM. A local user could exploit this to
cause a denial of service, or potentially execute arbitrary code as the
administrator.

Update instructions:

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

Ubuntu 18.04 LTS:
gdm3 3.28.2-0ubuntu1.4

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

References:
https://usn.ubuntu.com/usn/usn-3737-1
CVE-2018-14424

Package Information:
https://launchpad.net/ubuntu/+source/gdm3/3.28.2-0ubuntu1.4