Jun Mao discovered that Samba, an implementation of the SMB/CIFS protocol for Unix systems, is not properly handling certain offset values when processing chained SMB1 packets. This enables an unauthenticated attacker to write to an arbitrary memory location resulting in the possibility to execute arbitrary code with root privileges or to perform denial of service attacks by crashing the samba daemon. For the stable distribution , this problem has been fixed in version 3.2.5-4lenny12. This problem does not affect the versions in the testing and unstable distribution. We recommend that you upgrade your samba packages.