[Libguestfs] ATTN: Denial of service attack possible on libguestfs 1.21.x, libguestfs.1.22.0

Richard W.M. Jones rjones at redhat.com
Tue May 28 16:06:45 UTC 2013

There's a denial of service attack possible from guests on any program
that does inspection (eg. virt-inspector, many other virt-* tools,
virt-v2v, OpenStack).

The attack causes the host process to crash because of a double free.
It's probably not exploitable (definitely not on Fedora because of the
default memory hardening settings).

This patch contains the fix and a reproducer:


This affects libguestfs >= 1.21.6 and libguestfs 1.22.0 and 1.23.0.

I will include the fix in libguestfs >= 1.22.1 and >= 1.23.1.


Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-p2v converts physical machines to virtual machines.  Boot with a
live CD or over the network (PXE) and turn machines into KVM guests.

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