CVE-2016-9382: Undefined Security Weakness

Xen 4.0.x through 4.7.x mishandle x86 task switches to VM86 mode, which allows local 32-bit x86 HVM guest OS users to gain privileges or cause a denial of service guest OS crash by leveraging a guest operating system that uses hardware task switching and allows a new task to start in VM86 mode...

xen-kernel -- x86 task switch to VM86 mode mis-handled

The Xen Project reports: LDTR, just like TR, is purely a protected mode facility. Hence even when switching to a VM86 mode task, LDTR loading needs to follow protected mode semantics. This was violated by the code. On SVM AMD hardware: a malicious unprivileged guest process can escalate its...