CVE 2012-2111
The (1) CreateAccount, (2) OpenAccount, (3) AddAccountRights, and (4) RemoveAccountRights LSA RPC procedures in smbd in Samba 3.4.x before 3.4.17, 3.5.x before 3.5.15, and 3.6.x before 3.6.5 do not properly restrict modifications to the privileges database, which allows remote authenticated users to obtain the "take ownership" privilege via an LSA connection.
See the 
CVE page on Mitre.org
for more details.
