mm/ioremap.c in Linux 2.6 on 64-bit x86 systems allows local users to cause a denial of service or an information leak via an ioremap on a certain memory map that causes the iounmap to perform a lookup of a page that does not exist.
Exploitability
AV:LAC:LAu:NImpact
C:NI:NA:P2.1/AV:L/AC:L/Au:N/C:N/I:N/A:P