A tar security update has been released for Ubuntu 12.04 ESM, 14.04 ESM, 16.04 LTS, 18.04 LTS, 20.04 LTS, and 20.10.

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Ubuntu Security Notice USN-4692-1
January 13, 2021

tar vulnerabilities
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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
- Ubuntu 14.04 ESM
- Ubuntu 12.04 ESM

Summary:

Several security issues were fixed in tar.

Software Description:
- tar: GNU version of the tar archiving utility

Details:

Chris Siebenmann discovered that tar incorrectly handled extracting files
resized during extraction when invoked with the --sparse flag. An attacker
could possibly use this issue to cause a denial of service. This issue
only affected Ubuntu 12.04 ESM, Ubuntu 14.04 ESM, Ubuntu 16.04 LTS and
Ubuntu 18.04 LTS. (CVE-2018-20482)

Daniel Axtens discovered that tar incorrectly handled certain malformed
tar files. If a user or automated system were tricked into processing a
specially crafted tar archive, a remote attacker could use this issue to
cause tar to crash, resulting in a denial of service. (CVE-2019-9923)

Update instructions:

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

Ubuntu 20.10:
tar 1.30+dfsg-7ubuntu0.20.10.1

Ubuntu 20.04 LTS:
tar 1.30+dfsg-7ubuntu0.20.04.1

Ubuntu 18.04 LTS:
tar 1.29b-2ubuntu0.2

Ubuntu 16.04 LTS:
tar 1.28-2.1ubuntu0.2

Ubuntu 14.04 ESM:
tar 1.27.1-1ubuntu0.1+esm1

Ubuntu 12.04 ESM:
tar 1.26-4ubuntu1.2

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