It was discovered that Samba incorrectly handled dangling symlinks. A remote attacker could possibly use this issue to cause Samba to hang, resulting in a denial of service. This issue only applied to Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2017-9461)
In addition, this update fixes a regression introduced by USN-3267-1 that caused Samba to incorrectly handle non-wide symlinks to directories.