Description
WordPress Plugin Newsletters is prone to multiple vulnerabilities, including cross-site scripting and arbitrary file disclosure vulnerabilities. Exploiting these issues could allow an attacker to execute arbitrary script code in the browser of an unsuspecting user in the context of the affected site, allowing the attacker to steal cookie-based authentication credentials, or to view local files (eg. server configuration) in the context of the web server process, which may aid in launching further attacks. WordPress Plugin Newsletters version 4.6.5.3 is vulnerable; prior versions may also be affected.
Remediation
Update to plugin version 4.6.6 or latest
References
http://defensecode.com/advisories/DC-2017-01-012_WordPress_Tribulant_Newsletters_Plugin_Advisory.pdf
https://www.exploit-db.com/exploits/42129/
https://tribulant.com/docs/wordpress-mailing-list-plugin/11184/newsletters-4-6-6/