An APT security update has been released for Ubuntu Linux 16.04 LTS, 18.04 LTS, 20.04 LTS, and 20.10.

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Ubuntu Security Notice USN-4667-1
December 09, 2020

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

- Ubuntu 20.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

APT could be made to crash or stop responding if it opened a specially
crafted file.

Software Description:
- apt: Advanced front-end for dpkg

Details:

Kevin Backhouse discovered that APT incorrectly handled certain packages.
A local attacker could possibly use this issue to cause APT to crash or
stop responding, resulting in a denial of service.

Update instructions:

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

Ubuntu 20.10:
apt 2.1.10ubuntu0.1

Ubuntu 20.04 LTS:
apt 2.0.2ubuntu0.2

Ubuntu 18.04 LTS:
apt 1.6.12ubuntu0.2

Ubuntu 16.04 LTS:
apt 1.2.32ubuntu0.2

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

References:
  https://usn.ubuntu.com/4667-1
CVE-2020-27350

Package Information:
  https://launchpad.net/ubuntu/+source/apt/2.1.10ubuntu0.1
  https://launchpad.net/ubuntu/+source/apt/2.0.2ubuntu0.2
  https://launchpad.net/ubuntu/+source/apt/1.6.12ubuntu0.2
  https://launchpad.net/ubuntu/+source/apt/1.2.32ubuntu0.2