This indicates an attack attempt to exploit a directory-traversal vulnerability in Samba.
The vulnerability is a result of the application's failure to properly sanitize user shared name input before using it. As a result, a remote attacker can gain unauthorized access to the root folder.
Samba 3.4.5 and earlier versions.
Information Disclosure: Remote attackers can gain sensitive information from vulnerable systems.
Update your Samba configuration by setting "writeable=no" or/and "wide links = no" in the global section.