A Qt security update has been released for Ubuntu Linux 19.10, 18.04 LTS, and 16.04 LTS.

==========================================================================
Ubuntu Security Notice USN-4275-1
February 10, 2020

qtbase-opensource-src vulnerabilities
==========================================================================

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

- Ubuntu 19.10
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in Qt.

Software Description:
- qtbase-opensource-src: Qt 5 libraries

Details:

It was discovered that Qt incorrectly handled certain PPM images. If a user
or automated system were tricked into opening a specially crafted PPM file,
a remote attacker could cause Qt to crash, resulting in a denial of
service. This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS.
(CVE-2018-19872)

It was discovered that Qt incorrectly handled certain text files. If a user
or automated system were tricked into opening a specially crafted text
file, a remote attacker could cause Qt to crash, resulting in a denial of
service. This issue only affected Ubuntu 19.10. (CVE-2019-18281)

It was discovered that Qt incorrectly searched for plugins in the current
working directory. An attacker could possibly use this issue to execute
arbitrary code. (CVE-2020-0569)

It was discovered that Qt incorrectly searched for libraries relative to
the current working directory. An attacker could possibly use this issue to
execute arbitrary code. This issue only affected Ubuntu 19.10.
(CVE-2020-0570)

Update instructions:

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

Ubuntu 19.10:
libqt5core5a 5.12.4+dfsg-4ubuntu1.1
libqt5gui5 5.12.4+dfsg-4ubuntu1.1

Ubuntu 18.04 LTS:
libqt5core5a 5.9.5+dfsg-0ubuntu2.5
libqt5gui5 5.9.5+dfsg-0ubuntu2.5

Ubuntu 16.04 LTS:
libqt5core5a 5.5.1+dfsg-16ubuntu7.7
libqt5gui5 5.5.1+dfsg-16ubuntu7.7

After a standard system update you need to restart your session to make
all the necessary changes.

References:
  https://usn.ubuntu.com/4275-1
CVE-2018-19872, CVE-2019-18281, CVE-2020-0569, CVE-2020-0570

Package Information:
  https://launchpad.net/ubuntu/+source/qtbase-opensource-src/5.12.4+dfsg-4ubuntu1.1
  https://launchpad.net/ubuntu/+source/qtbase-opensource-src/5.9.5+dfsg-0ubuntu2.5
  https://launchpad.net/ubuntu/+source/qtbase-opensource-src/5.5.1+dfsg-16ubuntu7.7