A microcode_ctl security update has been released for CentOS 6.

CentOS-announce: CESA-2020:2433 Moderate CentOS 6 microcode_ctl Security Update

CentOS Errata and Security Advisory 2020:2433 Moderate

Upstream details at :   https://access.redhat.com/errata/RHSA-2020:2433

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

i386:
bc2910c9f73fe13f75c2921410c368230698ad20c41c6bc8f2b077e875bc5ecb microcode_ctl-1.17-33.26.el6_10.i686.rpm

x86_64:
d61387797006fdb5af23de80a5751ff3769dbdbb53d89839809dc98359b58125 microcode_ctl-1.17-33.26.el6_10.x86_64.rpm

Source:
29a7a32919a8d60ce03d01075170f32614032b89bd9bf8b3e46b76525018c082 microcode_ctl-1.17-33.26.el6_10.src.rpm