Description
WordPress Plugin Email Subscribers by Icegram Express-Email Marketing, Newsletters, Automation for WordPress & WooCommerce is prone to a security bypass vulnerability. Exploiting this issue may allow attackers to perform otherwise restricted actions and subsequently bypass the subscription form using fake email accounts. WordPress Plugin Email Subscribers by Icegram Express-Email Marketing, Newsletters, Automation for WordPress & WooCommerce version 3.5.13 is vulnerable; prior versions may also be affected.
Remediation
Update to plugin version 3.5.14 or latest
References
https://wordpress.org/support/topic/russian-spam-is-back-again/
https://plugins.svn.wordpress.org/email-subscribers/trunk/readme.txt
Related Vulnerabilities
WordPress Plugin Easy Registration Forms Cross-Site Scripting (1.8.3)
GlassFish Use of Hard-coded Credentials Vulnerability (CVE-2018-14324)
MediaWiki Exposure of Sensitive Information to an Unauthorized Actor Vulnerability (CVE-2013-1817)
OpenSSL Permissions, Privileges, and Access Controls Vulnerability (CVE-2010-1633)