A sudo security update has been released for CentOS 6.

CentOS Errata and Security Advisory 2020:0726 Important

Upstream details at :   https://access.redhat.com/errata/RHSA-2020:0726

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

i386:
ed17c727b0327a156d3dc917a95bc1fbf50a03bd6fcaa7f6155c63271b7ade9c sudo-1.8.6p3-29.el6_10.3.i686.rpm
17fd13eb5a39d752ca21fa7a1f0a452c77831cac1646efc232257d1ea31180b5 sudo-devel-1.8.6p3-29.el6_10.3.i686.rpm

x86_64:
34dc40c917e4080b159bb3fbea767eeea5d60275b0a3d4f715cde348a24e9886 sudo-1.8.6p3-29.el6_10.3.x86_64.rpm
17fd13eb5a39d752ca21fa7a1f0a452c77831cac1646efc232257d1ea31180b5 sudo-devel-1.8.6p3-29.el6_10.3.i686.rpm
2d709b3d4831234d92105aaa0b7207a41c73432005322781098de926c7ed1d4c sudo-devel-1.8.6p3-29.el6_10.3.x86_64.rpm

Source:
7fa30b571a1bcb5762dd8754a17001a71080475b7eb7dffc831ea1f2e6bd809d sudo-1.8.6p3-29.el6_10.3.src.rpm