Qemu emulator built with the e1000 NIC emulation support is vulnerable to an infinite loop issue. It could occur while processing transmit descriptor data when sending a network packet.
A privileged user inside guest could use this flaw to crash the Qemu instance resulting in DoS.
Upstream fix: ------------- -> https://lists.gnu.org/archive/html/qemu-devel/2015-09/msg01199.html
Buffer overflow in the sendcontrolmsg function in hw/char/virtio-serial-bus.c in QEMU before 2.4.0 allows guest users to cause a denial of service (QEMU process crash) via a crafted virtio control message.
The ne2000receive function in hw/net/ne2000.c in QEMU before 2.4.0.1 allows attackers to cause a denial of service (infinite loop and instance crash) or possibly execute arbitrary code via vectors related to receiving packets.
Integer overflow in the VNC display driver in QEMU before 2.1.0 allows attachers to cause a denial of service (process crash) via a CLIENTCUTTEXT message, which triggers an infinite loop.
The C+ mode offload emulation in the RTL8139 network card device model in QEMU, as used in Xen 4.5.x and earlier, allows remote attackers to read process heap memory via unspecified vectors.
Heap-based buffer overflow in the PCNET controller in QEMU allows remote attackers to execute arbitrary code by sending a packet with TXSTATUSSTARTPACKET set and then a crafted packet with TXSTATUSDEVICEOWNS set.
Due converting PIO to the new memory read/write api we no longer provide separate I/O region lenghts for read and write operations. As a result, reading from PIT Mode/Command register will end with accessing pit->channels with invalid index and potentially cause memory corruption and/or minor information leak.
A privileged guest user in a guest with QEMU PIT emulation enabled could potentially (tough unlikely) use this flaw to execute arbitrary code on the host with the privileges of the hosting QEMU process. (QEMU part of the vulnerability)
A privileged guest user in a guest could potentially (tough unlikely) use this flaw to execute arbitrary code on the host. (KVM part of the vulnerability)
Acknowledgements:
Red Hat would like to thank Matt Tait of Google's Project Zero security team for reporting this issue.