Gridbox 2.20.2.3 Media Manager folder navigation returns 403 Invalid token

Hello,

I am Brazilian, and my native language is Brazilian Portuguese (pt-BR). This report was prepared and translated with AI assistance after several diagnostic tests.

I am experiencing an issue with the Gridbox Media Manager after updating to Gridbox 2.20.2.3.

Environment:

Joomla: 6.1.2
Gridbox: 2.20.2.3
PHP: 8.4
Hosting: Hostinger
Cloudflare: Enabled
Media Manager root path: images
Language: Portuguese — Brazil (pt-BR)

The Media Manager opens correctly and displays the folders and files from the root images directory. However, when I click any subfolder, the folder is selected in the folder tree, but its contents are not loaded. The right panel continues displaying the contents of the root directory.

The failed request is:

POST /index.php?option=com_gridbox&task=uploader.executeAction

Server response:

403 Forbidden
Invalid token

After several tests, the following items were checked:

Directory permissions are 755 and file permissions are 644.
The PHP extensions fileinfo, GD, Imagick, mbstring and other Joomla requirements are enabled.
Joomla cache and expired cache were cleared.
Browser cookies were cleared.
The website was tested with a new login and in a private browser window.
Different PHP session cookie settings were tested.
Gridbox 2.20.2.3 was reinstalled over the existing installation without uninstalling it.
The failed request includes the Joomla session cookies.
Cloudflare is not caching the request (CF-Cache-Status: DYNAMIC).

The temporary workaround is to change the Media Manager root path directly to the required folder, for example:

images/eventos/2026/26070PL

When this direct path is configured, the files inside the folder are displayed correctly. This confirms that the directory is readable and that the problem occurs specifically when the Media Manager tries to navigate between folders through uploader.executeAction.

Based on the tests and the AI-assisted technical analysis, there are strong indications of a token validation issue in the Media Manager folder navigation.

Could you please confirm whether this is a known issue or regression in Gridbox 2.20.2.3 with Joomla 6.1.2? Is there a patch or recommended fix available?

I can provide additional screenshots, request payload information or server logs if necessary.

Website: https://www.portalleopolis.com.br/

Thank you.