OAuth Single Sign On – SSO (OAuth Client) <= 6.26.14 - Missing Authorization

The OAuth Single Sign On – SSO (OAuth Client) plugin for WordPress is vulnerable to unauthorized access in all versions up to, and including, 6.26.14. This is due to missing capability checks and authentication verification on the OAuth redirect functionality accessible via the 'oauthredirect' option parameter. This makes it possible for unauthenticated attackers to set the global redirect URL option via the redirect_url parameter granted they can access the site directly.