The MITRE CVE dictionary describes this issue as:
mount.cifs in cifs-utils 2.6 allows local users to determine the existence of arbitrary files or directories via the file path in the second argument, which reveals their existence in an error message.
Find out more about CVE-2012-1586 from the
MITRE CVE dictionary dictionary and
This issue affects the version of samba/samba3x as shipped with Red Hat Enterprise Linux 5. This issue is not currently planned to be addressed in future updates.