The Blackhole for Bad Bots WordPress plugin before 3.3.2 uses headers such as CF-CONNECTING-IP, CLIENT-IP etc to determine the IP address of requests hitting the blackhole URL, which allows them to be spoofed.
CVSS 3.1CRITICAL 9.1·Network·No auth·No interaction·EPSS 0.0167·Published 2022-04-04·Fixed in 3.3.2CWE-639