The emulation of far branch instructions (CALL, JMP, and RETF in Intel
assembly syntax, LCALL, LJMP, and LRET in AT&T assembly syntax)
incompletely performs privilege checks.
Malicious HVM guest user mode code may be able to elevate its
privileges to guest supervisor mode, or to crash the guest.
Red Hat would like to thank the Xen for reporting this issue.
This issue did not affect the versions of the kernel-xen package as shipped with Red Hat Enterprise Linux 5.
Created xen tracking bugs for this issue:
Affects: fedora-all [bug 1165204]