The Ultimate Member WordPress plugin before 2.6.7 does not prevent visitors from creating user accounts with arbitrary capabilities, effectively allowing attackers to create administrator accounts at will. This is actively being exploited in the wild.
https://github.com/ayinedjimi/wordpress-vulnerable-lab
https://github.com/TranKuBao/CVE-20233460
https://github.com/TranKuBao/CVE-2023-3460_FIX
https://github.com/diego-tella/CVE-2023-3460
https://github.com/Fire-Null/CVE-2023-3460
https://github.com/hheeyywweellccoommee/CVE-2023-3460-obgen