The Registration Forms User profile, Content Restriction, Spam Protection, Payment Gateways, Invitation Codes WordPress plugin before 3.7.1.6 does not properly escape user data before using it in a SQL statement in the wp-json/pie/v1/login REST API endpoint, leading to an SQL injection.
View the template here CVE-2021-24731.yaml
References:
https://nvd.nist.gov/vuln/detail/CVE-2021-24731