CVE-2021-22884

A flaw was found in nodejs. A denial of service is possible when the whitelist includes “localhost6”. When “localhost6” is not present in /etc/hosts, it is just an ordinary domain that is resolved via DNS over the network. If the attacker controls the victim’s DNS server or can spoof its responses, the DNS rebinding protection can be bypassed by using the “localhost6” domain. As long as the attacker uses the “localhost6” domain, they can still apply the attack described in CVE-2018-7160.

Mitigation

Ensure that 'localhost6' is part of /etc/hosts.
e.g.:

$ grep localhost6 /etc/hosts  
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6