Linux's netback driver allows frontends to control mapping of requests to request queues. When processing a request to set or change this mapping, some input validation was missing or flawed. A malicious or buggy frontend may cause the (usually privileged) backend to make out of bounds memory accesses, potentially resulting in one or more of privilege escalation, Denial of Service (DoS), or information leaks.

Red Hat Enterprise Linux 5 is the only supported version of Red Hat Enterprise Linux that ships with Xen support, and does not include the relevant build time configuration that would enable this code to be included.

Additional information:

Xen security advisory - https://xenbits.xen.org/xsa/advisory-270.html