Zero-Day Advisory

Fortinet Discovers WordPress SimpLy Gallery Blocks Plugin Cross-Site Scripting Vulnerability


Fortinet's FortiGuard Labs has discovered a cross-site scripting (XSS) vulnerability in WordPress SimpLy Gallery Blocks plugin.

SimpLy Gallery Blocks is a friendly, easy-to-use gallery plugin with a list of advanced options for creating responsive Image, Video, Audio galleries. It has over 10,000 active installations.

A stored cross-site scripting vulnerability has been discovered in Simply Gallery Blocks with Lightbox. The vulnerability exists in the Lightbox functionality where a user with low privileges is allowed to execute arbitrary script code within the context of the application. This vulnerability is caused by insufficient validation of image meta data.


FortiGuard Labs released the following FortiGate IPS signature which covers this specific vulnerability:

Released Aug 11, 2021

Upgrade to the version 2.2.1 or above.


Fortinet reported the vulnerability to Wordpress Plugins Team on August 9, 2021.

Galleryblocks Team confirmed the vulnerability on August 9, 2021.

Galleryblocks Team patched the vulnerability on August 12, 2021.


This vulnerability was discovered by Vishnupriya Ilango of Fortinet's FortiGuard Labs.

IPS Subscription

Fortinet customers who subscribe to Fortinet's intrusion prevention (IPS) service should be protected against this vulnerability with the appropriate configuration parameters in place. Fortinet's IPS service is one component of FortiGuard Subscription Services, which also offer comprehensive solutions such as antivirus, Web content filtering and antispam capabilities. These services enable protection against threats on both application and network layers. FortiGuard Services are continuously updated by FortiGuard Labs, which enables Fortinet to deliver a combination of multi-layered security intelligence and true zero-day protection from new and emerging threats. These updates are delivered to all FortiGate, FortiMail and FortiClient products. Fortinet strictly follows responsible disclosure guidelines to ensure optimum protection during a threat's lifecycle.