A krb5-appl security update has been released for CentOS 6.

CentOS-announce: CESA-2020:1349 Important CentOS 6 krb5-appl Security Update

CentOS Errata and Security Advisory 2020:1349 Important

Upstream details at :   https://access.redhat.com/errata/RHSA-2020:1349

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

i386:
2cffa95c73d5b9662a971f9eddbd67ce1bf396911127e3d31b52caf60c90d984 krb5-appl-clients-1.0.1-10.el6_10.i686.rpm
b7af46946a015ebf805991e9a9341163aec0ecbd1d9edb7cfc0234fbcc2b40cb krb5-appl-servers-1.0.1-10.el6_10.i686.rpm

x86_64:
6309ea0347c159b5270abe84ad36d6e6d94c563c41ba107190a79a2a8210ccb6 krb5-appl-clients-1.0.1-10.el6_10.x86_64.rpm
3dced1fba4d6aa65537dedc85ef52ec6d7093edd165279e6284aac7e326f5579 krb5-appl-servers-1.0.1-10.el6_10.x86_64.rpm

Source:
24b1ce1567946fff000259c1904aeb7b4736bbd067b6ca929d9869dcab4787e7 krb5-appl-1.0.1-10.el6_10.src.rpm