Several vulnerabilities were discovered in Xen, a hypervisor.
For CVE-2012-2934,
Xen refuses to start domUs on affected systems
unless the allow_unsafe option is passed.
For the stable distribution (squeeze), these problems have been fixed
in version 4.0.1-5.2.
For the testing distribution (wheezy) and the unstable distribution
(sid), these problems have been fixed in version
4.1.3~rc1+hg-20120614.a9c0a89c08f2-1.
We recommend that you upgrade your xen packages.