(RHSA-2017:1206) Important: qemu-kvm security update

Kernel-based Virtual Machine (KVM) is a full virtualization solution for Linux on a variety of architectures. The qemu-kvm package provides the user-space component for running virtual machines that use KVM.

Security Fix(es):

• A heap buffer overflow flaw was found in QEMU’s Cirrus CLGD 54xx VGA emulator’s VNC display driver support; the issue could occur when a VNC client attempted to update its display after a VGA operation is performed by a guest. A privileged user/process 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. (CVE-2016-9603)

• 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. (CVE-2017-7980)

• An out-of-bounds memory access issue was found in QEMU’s VNC display driver support. The vulnerability could occur while refreshing the VNC display surface area in the ‘vnc_refresh_server_surface’. A user/process inside a guest could use this flaw to crash the QEMU process, resulting in a denial of service. (CVE-2017-2633)

• 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. (CVE-2017-7718)

Red Hat would like to thank Jiangxin (PSIRT Huawei Inc.) and Li Qiang (Qihoo 360 Gear Team) for reporting CVE-2017-7980 and Jiangxin (PSIRT Huawei Inc.) for reporting CVE-2017-7718.