Qemu's user mode networking stack(SLiRP) is vulnerable to a predictable temporary file names creation flaw. It occurs when using -smb option.
An unprivileged user could use this to thwart instantiation of Qemu guests, resulting in DoS.
Created qemu tracking bugs for this issue:
Affects: fedora-all [bug 1222894]
This issue affects the versions of the kvm and xen packages as shipped with Red Hat Enterprise Linux 5, the versions of the qemu-kvm packages as shipped with Red Hat Enterprise Linux 6 and 7, and the versions of qemu-kvm-rhev packages as shipped with Red Hat Enterprise Virtualization 3.
This has been rated as having Moderate security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.
qemu-2.3.0-5.fc22 has been pushed to the Fedora 22 stable repository. If problems still persist, please make note of it in this bug report.
qemu-2.1.3-8.fc21 has been pushed to the Fedora 21 stable repository. If problems still persist, please make note of it in this bug report.