Xen · Xen · CVE-2014-7155
**Name of the Vulnerable Software and Affected Versions**
Xen versions 4.4.x and earlier
**Description**
The issue is related to the x86 emulate function in Xen, which does not properly check supervisor mode permissions. This allows local HVM users to cause a denial of service, resulting in a guest crash, or gain guest kernel mode privileges. The exploitation vectors involve specific instructions, including `HLT`, `LGDT`, `LIDT`, or `LMSW`.
**Recommendations**
For Xen versions 4.4.x and earlier, consider restricting the use of the x86 emulate function until a patch is available. As a temporary workaround, limiting the execution of `HLT`, `LGDT`, `LIDT`, or `LMSW` instructions may help minimize the risk of exploitation. At the moment, there is no information about a newer version that contains a fix for this vulnerability.