A qemu-kvm security update has been released for CentOS 6.

CentOS-announce: CESA-2020:4056 Important CentOS 6 qemu-kvm Security Update

CentOS Errata and Security Advisory 2020:4056 Important

Upstream details at :   https://access.redhat.com/errata/RHSA-2020:4056

The following updated files have been uploaded and are currently
syncing to the mirrors: ( sha256sum Filename )

i386:
110ff2997980505e2c755ad69dc69c16bb5c233bbcd00c2526ea651016daee45 qemu-guest-agent-0.12.1.2-2.506.el6_10.8.i686.rpm

x86_64:
a4fd9d13950bd622a0349d761f720561d2837a4d81bba234a59b735b27049627 qemu-guest-agent-0.12.1.2-2.506.el6_10.8.x86_64.rpm
88b1f7d416a92562d3865f3ef460923ca3297f6ab5da6fc1b3e88477fddf31c1 qemu-img-0.12.1.2-2.506.el6_10.8.x86_64.rpm
49da23eb27685168ab6afd80055eefa09fe2c0698c67f71572041aac19e6de94 qemu-kvm-0.12.1.2-2.506.el6_10.8.x86_64.rpm
c870e3965e0ef57010331aa8745056aecfa1ecc5688543a1f8bfcdab7fec27fa qemu-kvm-tools-0.12.1.2-2.506.el6_10.8.x86_64.rpm

Source:
c274069cbe1d9c56734995fb975a166328fab9e017a2727e39267934d0d88741 qemu-kvm-0.12.1.2-2.506.el6_10.8.src.rpm