A slapi-nis bugfix update has been released for CentOS 7.

CEBA-2021:0861 CentOS 7 slapi-nis BugFix Update

CentOS Errata and Bugfix Advisory 2021:0861

Upstream details at :   https://access.redhat.com/errata/RHBA-2021:0861

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

x86_64:
406370b48821a02c6cd77913d2bbfb9b1c8a38d584ee789492dbdbda1796c482 slapi-nis-0.56.5-3.el7_9.x86_64.rpm

Source:
0199a9051530c26a95f4b6454e9d3a2ad18715f01785cf9d51976a55fc3b3a9b slapi-nis-0.56.5-3.el7_9.src.rpm