Looking for logging into the Vbulletin Api site and are not getting the correct working link for it? In such a case, you can use the links given here by searching your desired login page in the search box. If the page is present on our website then you will get all the links related to the Vbulletin Api site. After that you can login as usual with your login credentials.
https://www.vbulletin.com/forum/forum/vbulletin-4/vbulletin-4-questions-problems-and-troubleshooting/3960966-curl-mobile-api-login-vs-login-bridge-simple-login-embed
https://www.vbulletin.org/forum/showthread.php?t=323013
http://vb5support.com/resources/api/index.html
http://forum.vbulletin-germany.com/showthread.php/49661-API-Login-in-vBulletin-4-0
https://stackoverflow.com/questions/2476975/how-to-integrate-vbulletin-auth-with-my-site
https://packagist.org/packages/signes/vbulletin-api-php
https://www.exploit-db.com/exploits/40114
https://docs.oneall.com/plugins/guide/social-login-vbulletin/4/
https://support.cloudflare.com/hc/en-us/articles/202032590-Using-Cloudflare-with-vBulletin-forums
https://webmasters.stackexchange.com/questions/61572/vbulletin-api-can-i-pull-thread-users-etc-from-third-party-forums
https://www.freelancer.com/projects/php-software-architecture/vbulletin-authentication-external-api/
https://www.mediawiki.org/wiki/Extension:VBulletin/Users_Integration
https://www.drupal.org/project/drupalvb/issues/269295