CVE-2017-2619

A race condition was found in samba server. A malicious samba client could use this flaw to access files and directories in areas of the server file system not exported under the share definitions.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Add the parameter:

unix extensions = no

to the [global] section of your smb.conf and restart smbd. This prevents SMB1 clients from creating symlinks on the exported file system using SMB1.

However, if the same region of the file system is also exported using NFS, NFS clients can create symlinks that potentially can also hit the race condition. For non-patched versions of Samba we recommend only exporting areas of the file system by either SMB or NFS, not both.