Multiple integer overflows in the (1) agp_allocate_memory and (2) agp_create_user_memory functions in drivers/char/agp/generic.c in the Linux kernel before 2.6.38.5 allow local users to trigger buffer overflows, and consequently cause a denial of service (system crash) or possibly have unspecified other impact, via vectors related to calls that specify a large number of memory pages.
git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=b522f02184b413955f3bc952e3776ce41edc6355
openwall.com/lists/oss-security/2011/04/21/4
openwall.com/lists/oss-security/2011/04/22/7
rhn.redhat.com/errata/RHSA-2011-0927.html
www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.38.5
www.securityfocus.com/bid/47535
bugzilla.redhat.com/show_bug.cgi?id=698998
lkml.org/lkml/2011/4/14/294
lkml.org/lkml/2011/4/19/400