Xen in the Linux kernel, when running a guest on a host without hardware assisted paging (HAP), allows guest users to cause a denial of service (invalid pointer dereference and hypervisor crash) via the SAHF instruction.
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Xen | Xen | * | 3.3.0 (excluding) |
| Red Hat Enterprise Linux 5 | RedHat | kernel-0:2.6.18-274.3.1.el5 | * |
| Red Hat Enterprise Linux 5.6 EUS - Server Only | RedHat | kernel-0:2.6.18-238.31.1.el5 | * |
| Xen-3.1 | Ubuntu | hardy | * |
| Xen-3.2 | Ubuntu | hardy | * |
| Xen-3.3 | Ubuntu | maverick | * |
| Xen-3.3 | Ubuntu | natty | * |