Several security issues were fixed in Samba.

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Ubuntu Security Notice USN-4167-2
October 29, 2019

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

- Ubuntu 14.04 ESM
- Ubuntu 12.04 ESM

Summary:

Several security issues were fixed in Samba.

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

Details:

USN-4167-1 fixed several vulnerabilities in Samba. This update provides
the corresponding update for Ubuntu 12.04 ESM and Ubuntu 14.04 ESM.

Original advisory details:

 Michael Hanselmann discovered that the Samba client code incorrectly
 handled path separators. If a user were tricked into connecting to a
 malicious server, a remote attacker could use this issue to cause the
 client to access local pathnames instead of network pathnames.
 (CVE-2019-10218)

 Adam Xu discovered that Samba incorrectly handled the dirsync LDAP control.
 A remote attacker with "get changes" permissions could possibly use this
 issue to cause Samba to crash, resulting in a denial of service. This issue
 only affected Ubuntu 14.04 ESM. (CVE-2019-14847)

Update instructions:

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

Ubuntu 14.04 ESM:
  libsmbclient                    2:4.3.11+dfsg-0ubuntu0.14.04.20+esm3
  samba                           2:4.3.11+dfsg-0ubuntu0.14.04.20+esm3

Ubuntu 12.04 ESM:
  libsmbclient                    2:3.6.25-0ubuntu0.12.04.19
  samba                           2:3.6.25-0ubuntu0.12.04.19

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

References:
  https://usn.ubuntu.com/4167-2
  https://usn.ubuntu.com/4167-1
  CVE-2019-10218, CVE-2019-14847