link to Patchstack from SECURITY.md

Author: dannyvankooten

SECURITY.md

@@ -5,4 +5,6 @@ We appreciate your efforts to responsibly disclose your findings, and will make
 
 ## Reporting a Vulnerability
 
-To report a security issue, please email us at support@mc4wp.com or use the GitHub Security Advisory "[Report a Vulnerability](https://github.com/ibericode/mailchimp-for-wordpress/security/advisories/new)" tab.
+To report a security issue, please use the [Patchstack Vulnerability Disclosure Program](https://patchstack.com/database/vdp/8c215d34-dc57-4167-8af8-a9863cb63668). The Patchstack team will assist with verification, CVE assignment, and notifying the developers of this plugin.
+
+You can also email us at support@mc4wp.com or use the GitHub Security Advisory "[Report a Vulnerability](https://github.com/ibericode/mailchimp-for-wordpress/security/advisories/new)" tab.