Zhenzhong Duan

**Name of the Vulnerable Software and Affected Versions** Xen versions 3.3 through 4.3 **Description** The issue allows local HVM guests with access to memory mapped I/O regions to cause a denial of service. This can result in CPU consumption and possibly hypervisor or guest kernel panic via a crafted GFN range. The `vmx set uc mode` function is involved when disabling caches. **Recommendations** For Xen versions 3.3 through 4.3, consider disabling the `vmx set uc mode` function as a temporary workaround until a patch is available. Restrict access to memory mapped I/O regions to minimize the risk of exploitation. At the moment, there is no information about a newer version that contains a fix for this vulnerability.