kvm_set_irq() has an internal buffer of three irq routing entries, allowing connecting a GSI to three IRQ chips or on MSI. However setup_routing_entry() does not properly enforce this, allowing three irqchip routes followed by an MSI route to overflow the buffer.
An unprivileged local user could use this flaw to crash the system or potentialy escalate their privileges.
This issue did not affect the versions of the Linux kernel as shipped with Red Hat Enterprise Linux 5 and Red Hat Enterprise MRG. This issue was addressed in Red Hat Enterprise Linux 6 via RHSA-2012:0743 https://rhn.redhat.com/errata/RHSA-2012-0743.html
This issue has been addressed in following products:
Red Hat Enterprise Linux 6
Via RHSA-2012:0743 https://rhn.redhat.com/errata/RHSA-2012-0743.html