Gallery by BestWebSoft < 4.7.0 – Author+ Stored Cross-Site Scripting | CVE 2023-0764

Description

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.

Proof of Concept

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.