Please Install the Updated Packages.
The xen packages contain administration tools and the xend service for managing the kernel-xen kernel for virtualization on Red Hat Enterprise Linux. It was found that the xc_try_bzip2_decode() and xc_try_lzma_decode() decode routines did not correctly check for a possible buffer size overflow in the decoding loop. As well, several integer overflow flaws and missing error/range checking were found that could lead to an infinite loop. A privileged guest user could use these flaws to crash the guest or, possibly, execute arbitrary code in the privileged management domain (Dom0). (CVE-2011-1583) All xen users are advised to upgrade to these updated packages, which contain backported patches to correct these issues. The system must be rebooted for this update to take effect.
xen on CentOS 5
Updated on 2015-03-25