Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
ISC DHCP is not affected. It doesn't act as a DNS resolver. This is a BIND server-side issue. ISC DHCP uses portions of the ISC BIND libraries (primarily libdns, omapi, and libisccfg) only to support DDNS (TSIG support, DNS message construction/parsing, DHCID generation), OMAPI related operations, basic functions (configuration handling, data structures, logging, networking primitives).