The sisfb_ioctl function in drivers/video/sis/sis_main.c in the Linux kernel before 2.6.36-rc6 does not properly initialize a certain structure member, which allows local users to obtain potentially sensitive information from kernel stack memory via an FBIOGET_VBLANK ioctl call.
http://lists.opensuse.org/opensuse-security-announce/2010-12/msg00004.html
http://lists.opensuse.org/opensuse-security-announce/2011-01/msg00000.html
http://lists.opensuse.org/opensuse-security-announce/2011-01/msg00001.html
http://lists.opensuse.org/opensuse-security-announce/2011-02/msg00000.html
https://bugzilla.redhat.com/show_bug.cgi?id=648665
http://secunia.com/advisories/42778
http://secunia.com/advisories/42801
http://www.debian.org/security/2010/dsa-2126
http://www.mandriva.com/security/advisories?name=MDVSA-2011:051
http://www.openwall.com/lists/oss-security/2010/09/25/2
http://www.openwall.com/lists/oss-security/2010/10/06/6
http://www.openwall.com/lists/oss-security/2010/10/07/1
http://www.openwall.com/lists/oss-security/2010/10/25/3