Gallery by BestWebSoft < 4.7.0 - Author+ Stored Cross-Site Scripting

The plugin does not perform proper sanitization of gallery information, leading to a Stored Cross-Site Scription vulnerability. The attacker must have at least the privileges of the Author role.

PoC

1. Go to Galleries > Add New. 2. Click “Add Media” and choose or upload an image. 3. When publishing (or updating) the Gallery, intercept the request and change the POST parameter with name gllr_image_text%5B13%5D (note the 13 is an ID and will be different in each case). Set the value to " onload="alert(/XSS/)" e=". 4. Load the Gallery on the frontend and see the alert. The XSS can also be attained with the same payload in the gllr_image_alt_tag%5B13%5D parameter.