CVE-2017-7718

En el archivo hw/display/cirrus_vga_rop.h en QEMU (también se conoce como Quick Emulator), permite a los usuarios privilegiados del sistema operativo invitado local causar una denegación de servicio (lectura fuera de límites y bloqueo del proceso QEMU) por medio de vectores relacionados con el copiado de datos VGA mediante las funciones cirrus_bitblt_rop_fwd_transp_ y cirrus_bitblt__.

An out-of-bounds access issue was found in QEMU's Cirrus CLGD 54xx VGA Emulator support. The vulnerability could occur while copying VGA data using bitblt functions (for example, cirrus_bitblt_rop_fwd_transp_). A privileged user inside a guest could use this flaw to crash the QEMU process, resulting in denial of service.

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.