The reply_sesssetup_and_X_spnego function in sesssetup.c in smbd in Samba before 3.4.8 and 3.5.x before 3.5.2 allows remote attackers to trigger an out-of-bounds read, and cause a denial of service (process crash), via a \xff\xff security blob length in a Session Setup AndX request.
https://bugzilla.samba.org/show_bug.cgi?id=7254
https://bugzilla.redhat.com/show_bug.cgi?id=594921
http://www.vupen.com/english/advisories/2010/1933
http://www.stratsec.net/Research/Advisories/Samba-Multiple-DoS-Vulnerabilities-%28SS-2010-005%29
http://www.mandriva.com/security/advisories?name=MDVSA-2010:141
http://security-tracker.debian.org/tracker/CVE-2010-1642
http://samba.org/samba/history/samba-3.5.2.html
http://samba.org/samba/history/samba-3.4.8.html
http://git.samba.org/?p=samba.git%3Ba=commit%3Bh=9280051bfba337458722fb157f3082f93cbd9f2b