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.

Red Hat libvirt 0.2.0 through 0.8.2 creates iptables rules with improper mappings of privileged source ports, which allows guest OS users to bypass intended access restrictions by leveraging IP address and source-port values, as demonstrated by copying and deleting an NFS directory tree.

Red Hat libvirt, possibly 0.6.0 through 0.8.2, creates new images without setting the user-defined backing-store format, which allows guest OS users to read arbitrary files on the host OS via unspecified vectors.

Red Hat libvirt, possibly 0.6.1 through 0.8.2, looks up disk backing stores without referring to the user-defined main disk format, which might allow guest OS users to read arbitrary files on the host OS, and possibly have unspecified other impact, via unknown vectors.