CVE-2017-7980

Desbordamiento de búfer basado en memoria dinámica (heap) en Cirrus CLGD 54xx VGA Emulator en Quick Emulator (Qemu) en versiones 2.8 y anteriores permite que los usuarios invitados del sistema operativo ejecuten código arbitrario o provoquen una denegación de servicio (DoS) mediante vectores relacionados con un cliente VNC que actualiza su display después de una operación VGA.

An out-of-bounds r/w access issue was found in QEMU's Cirrus CLGD 54xx VGA Emulator support. The vulnerability could occur while copying VGA data via various bitblt functions. A privileged user inside a guest could use this flaw to crash the QEMU process or, potentially, execute arbitrary code on the host with privileges of the QEMU process.

Li Qiang discovered that QEMU incorrectly handled VirtFS directory sharing. A privileged attacker inside the guest could use this issue to cause QEMU to crash, resulting in a denial of service. Jiangxin discovered that QEMU incorrectly handled the Cirrus VGA device. A privileged attacker inside the guest could use this issue to cause QEMU to crash, resulting in a denial of service. Li Qiang and Jiangxin discovered that QEMU incorrectly handled the Cirrus VGA device when being used with a VNC connection. A privileged attacker inside the guest could use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code on the host. In the default installation, when QEMU is used with libvirt, attackers would be isolated by the libvirt AppArmor profile. Various other issues were also addressed.