The do_anonymous_page function in mm/memory.c in the Linux kernel before 2.6.27.52, 2.6.32.x before 2.6.32.19, 2.6.34.x before 2.6.34.4, and 2.6.35.x before 2.6.35.2 does not properly separate the stack and the heap, which allows context-dependent attackers to execute arbitrary code by writing to the bottom page of a shared memory segment, as demonstrated by a memory-exhaustion attack against the X.Org X server.
https://rhn.redhat.com/errata/RHSA-2010-0661.html
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A13247
https://bugzilla.redhat.com/show_bug.cgi?id=606611
http://www.vmware.com/security/advisories/VMSA-2011-0009.html
http://www.vmware.com/security/advisories/VMSA-2011-0007.html
http://www.securityfocus.com/archive/1/517739/100/0/threaded
http://www.redhat.com/support/errata/RHSA-2010-0882.html
http://www.redhat.com/support/errata/RHSA-2010-0670.html
http://www.redhat.com/support/errata/RHSA-2010-0660.html
http://www.mandriva.com/security/advisories?name=MDVSA-2011:051
http://www.mandriva.com/security/advisories?name=MDVSA-2010:198
http://www.mandriva.com/security/advisories?name=MDVSA-2010:172
http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.35.2
http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.34.4
http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.32.19
http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.27.52
http://www.debian.org/security/2010/dsa-2094
http://securitytracker.com/id?1024344
http://lists.vmware.com/pipermail/security-announce/2011/000133.html