CVE 2009-2813
Samba 3.4 before 3.4.2, 3.3 before 3.3.8, 3.2 before 3.2.15, and 3.0.12 through 3.0.36, as used in the SMB subsystem in Apple Mac OS X 10.5.8 when Windows File Sharing is enabled, Fedora 11, and other operating systems, does not properly handle errors in resolving pathnames, which allows remote authenticated users to bypass intended sharing restrictions, and read, create, or modify files, in certain circumstances involving user accounts that lack home directories.
See the 
CVE page on Mitre.org
for more details.
