Integer overflow in libvirt before 0.9.3 allows remote authenticated users to cause a denial of service (libvirtd crash) and possibly execute arbitrary code via a crafted VirDomainGetVcpus RPC call that triggers memory corruption.
libvirtd in libvirt before 0.9.0 does not use thread-safe error reporting, which allows remote attackers to cause a denial of service (crash) by causing multiple threads to report errors at the same time.