A Samba regression is available for Ubuntu Linux 16.04 LTS to address an issue introduced by USN-4341-1.

USN-4341-3: Samba regression

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Ubuntu Security Notice USN-4341-3
April 29, 2020

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

- Ubuntu 16.04 LTS

Summary:

USN-4341-1 introduced a regression in Samba.

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

Details:

USN-4341-1 fixed vulnerabilities in Samba. The updated packages for
Ubuntu 16.04 LTS introduced a regression when using LDAP. This update fixes
the problem.

We apologize for the inconvenience.

Original advisory details:

It was discovered that Samba incorrectly handled certain LDAP queries. A
remote attacker could possibly use this issue to cause Samba to consume
resources, resulting in a denial of service. (CVE-2020-10704)

Update instructions:

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

Ubuntu 16.04 LTS:
samba 2:4.3.11+dfsg-0ubuntu0.16.04.27

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

References:
  https://usn.ubuntu.com/4341-3
  https://usn.ubuntu.com/4341-1
  https://launchpad.net/bugs/1875798

Package Information:
  https://launchpad.net/ubuntu/+source/samba/2:4.3.11+dfsg-0ubuntu0.16.04.27I