client/mount.cifs.c in mount.cifs in smbfs in Samba 3.4.5 and earlier does not verify that the (1) device name and (2) mountpoint strings are composed of valid characters, which allows local users to cause a denial of service (mtab corruption) via a crafted string.
http://git.samba.org/?p=samba.git%3Ba=commit%3Bh=a065c177dfc8f968775593ba00dffafeebb2e054
http://lists.opensuse.org/opensuse-security-announce/2010-04/msg00001.html
http://lists.opensuse.org/opensuse-security-announce/2010-08/msg00001.html
http://secunia.com/advisories/39317
http://security.gentoo.org/glsa/glsa-201206-29.xml
http://www.mandriva.com/security/advisories?name=MDVSA-2010:090