Description
WordPress Plugin Popup, Optin Form & Email Newsletters for Mailchimp, HubSpot, Aweber-MailOptin is prone to a security bypass vulnerability. Exploiting this issue may allow attackers to perform otherwise restricted actions and subsequently call some of the AJAX actions. WordPress Plugin Popup, Optin Form & Email Newsletters for Mailchimp, HubSpot, Aweber-MailOptin version 1.2.35.1 is vulnerable; prior versions may also be affected.
Remediation
Update to plugin version 1.2.35.2 or latest
References
https://sploitus.com/exploit?id=WPEX-ID:BE8A7C53-D9C5-413C-A561-26B48502F7BE
https://plugins.svn.wordpress.org/mailoptin/trunk/changelog.txt