Summary A Critical vulnerability exists in the "Plugins::add()" function. The system fails to properly validate the file paths within uploaded ZIP archives. This allows an attacker to perform a Zip Slip attack, leading to Arbitrary File Write and Remote Code Execution (RCE) by overwriting sensitive .php files outside the designated plugins directory. Details The vulnerability is located in Plugins.php. While the "testZipFile" function attempts to validate that the ZIP contains only one root folder, it does not sanitize or validate the individual file paths within that folder. // Vulnerable logic in Plugins.php for ($index = 0; $index < $zipFile->numFiles; $index++) { $data = $zipFile->statIndex($index); $path = explode('/', $data['name']); if (count($path) > 1) { $folders[$path[0]] = $path[0]; } } An attacker can bypass this check by naming a file "ValidPluginName/../../shell.php". The explode function will see ValidPluginName as the root folder, satisfying the "count($folders) != 1" check. However, during extraction, the "../../" sequence triggers a path traversal, allowing the file to be written anywhere the web server has permissions the root directory. PoC Prepare Malicious ZIP: Use a tool (like evilarc) or a script to create a ZIP file where one of the entries is named: "MyPlugin/../../rce.php" Inject Payload: Inside rce.php, put a simple shell: "<?php system($_GET['cmd']); ?>" Upload: Navigate to the "Add Plugin" section in FacturaScripts and upload the malicious ZIP. Execution: Access the shell via https://target.com/rce.php?cmd=whoami. Impact Confidentiality: High (Attacker can read all database configs and files). Integrity: High (Attacker can modify any file on the server). Availability: High (Attacker can delete the entire installation). «https://github.com/ZeroXJacks/CVEs/blob/main/2026/CVE-2026-27891.md»