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Ubuntu Security Notice USN-4454-1
August 10, 2020

samba vulnerability
==========================================================================

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

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

Summary:

Samba could be made to crash if it received specially crafted network
traffic.

Software Description:
- samba: SMB/CIFS file, print, and login server for Unix

Details:

Martin von Wittich and Wilko Meyer discovered that Samba incorrectly
handled certain empty UDP packets when being used as a AD DC NBT server. A
remote attacker could possibly use this issue to cause Samba to crash,
resulting in a denial of service.

Update instructions:

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

Ubuntu 20.04 LTS:
  samba                           2:4.11.6+dfsg-0ubuntu1.4

Ubuntu 18.04 LTS:
  samba                           2:4.7.6+dfsg~ubuntu-0ubuntu2.18

Ubuntu 16.04 LTS:
  samba                           2:4.3.11+dfsg-0ubuntu0.16.04.29

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

References:
  https://usn.ubuntu.com/4454-1
  CVE-2020-14303

Package Information:
  https://launchpad.net/ubuntu/+source/samba/2:4.11.6+dfsg-0ubuntu1.4
  https://launchpad.net/ubuntu/+source/samba/2:4.7.6+dfsg~ubuntu-0ubuntu2.18
  https://launchpad.net/ubuntu/+source/samba/2:4.3.11+dfsg-0ubuntu0.16.04.29