As per upstream advisory: In versions of BIND that use the libuv network manager (9.16.x is the only stable branch affected) an incorrectly specified maximum buffer size allows a specially crafted large TCP payload to trigger an assertion failure when it is received. An attacker who can establish a TCP connection with the server and send data on that connection can exploit this to trigger the assertion failure, causing the server to exit.
Acknowledgments: Name: ISC Upstream: Emanuel Almeida (Cisco Systems, Inc)
Statement: This version only affects bind-9.16.x. Therefore versions of bind package shipped with Red Hat Enterprise Linux are not affected by this flaw.
External References: https://kb.isc.org/docs/cve-2020-8620