A xdg-utils regression update has been released for Ubuntu 16.04 LTS, 18.04 LTS, 20.04 LTS, and 20.10.

USN-4649-2: xdg-utils regression

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Ubuntu Security Notice USN-4649-2
January 12, 2021

xdg-utils regression
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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:

USN-4649-1 introduced a regression in xdg-utils.

Software Description:
- xdg-utils: desktop integration utilities from freedesktop.org

Details:

USN-4649-1 fixed vulnerabilities in xdg-utils. That update caused a regression
by removing the --attach functionality in thunderbird and others applications.
This update fix the problem by reverting these changes.

Original advisory details:

Jens Mueller discovered that xdg-utils incorrectly handled certain URI.
An attacker could possibly use this issue to expose sensitive information.

Update instructions:

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

Ubuntu 20.10:
xdg-utils 1.1.3-2ubuntu1.20.10.2

Ubuntu 20.04 LTS:
xdg-utils 1.1.3-2ubuntu1.20.04.2

Ubuntu 18.04 LTS:
xdg-utils 1.1.2-1ubuntu2.5

Ubuntu 16.04 LTS:
xdg-utils 1.1.1-1ubuntu1.16.04.5

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

References:
  https://usn.ubuntu.com/4649-2
  https://usn.ubuntu.com/4649-1
  https://launchpad.net/bugs/1909941

Package Information:
  https://launchpad.net/ubuntu/+source/xdg-utils/1.1.3-2ubuntu1.20.10.2
  https://launchpad.net/ubuntu/+source/xdg-utils/1.1.3-2ubuntu1.20.04.2
  https://launchpad.net/ubuntu/+source/xdg-utils/1.1.2-1ubuntu2.5
  https://launchpad.net/ubuntu/+source/xdg-utils/1.1.1-1ubuntu1.16.04.5