When guest sends udp packet with source port and source addr 0, uninitialized socket is picked up when looking for matching and already created udp sockets, and later passed to sosendto() where NULL pointer dereference is hit during so->slirp->vnetwork_mask.s_addr access. Only guests using qemu user networking are affected. Acknowledgements: Red Hat would like to thank Xavier Mehrenberger and Stephane Duverger of Airbus for reporting this issue.
Statement: This issue did not affect the kvm package as shipped with Red Hat Enterprise Linux 5. Red Hat Product Security has rated this issue as having Low security impact. Future qemu-kvm updates for Red Hat Enterprise Linux 6 and 7 may address this issue. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.
Upstream patch submission: http://lists.nongnu.org/archive/html/qemu-devel/2014-09/msg03543.html
Created qemu tracking bugs for this issue: Affects: fedora-all [bug 1144821]
qemu-2.1.2-2.fc21 has been pushed to the Fedora 21 stable repository. If problems still persist, please make note of it in this bug report.
qemu-1.6.2-9.fc20 has been pushed to the Fedora 20 stable repository. If problems still persist, please make note of it in this bug report.
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2015:0349 https://rhn.redhat.com/errata/RHSA-2015-0349.html
This issue has been addressed in the following products: RHEV-H and Agents for RHEL-7 Via RHSA-2015:0624 https://rhn.redhat.com/errata/RHSA-2015-0624.html