I am not a security expert but I always start with OWASP Top 10 for bare minimum: https://owasp.org/www-project-top-ten/ https://owasp.org/www-project-top-ten/

I am not a security expert but I always start with OWASP Top 10 for bare minimum: https://owasp.org/www-project-top-ten/ https://owasp.org/www-project-top-ten/ Go through each item and test your application for vulnerabilities against those.