CVE 2015-3214
The pit_ioport_read in i8254.c in the Linux kernel before 2.6.33 and QEMU before 2.3.1 does not distinguish between read lengths and write lengths, which might allow guest OS users to execute arbitrary code on the host OS by triggering use of an invalid index.
See the 
CVE page on Mitre.org
for more details.
