Samba Symlink Directory Traversal Vulnerability

The default configuration of smbd in Samba before 3.3.11, 3.4.x before 3.4.6, and 3.5.x before 3.5.0rc3, when a writable share exists, allows remote authenticated users to leverage a directory traversal vulnerability, and access arbitrary files, by using the symlink command in smbclient to create a symlink containing .. (dot dot) sequences, related to the combination of the unix extensions and wide links options.