Invoice Ninja before 5.10.43 allows remote code execution from a pre-authenticated route when an attacker knows the APPKEY. This is exacerbated by .env files, available from the product's repository, that have default APPKEY values. The route/{hash} route defined in the invoiceninja/routes/client.php file can be accessed without authentication. The parameter {hash} is passed to the function decrypt that expects a Laravel ciphered value containing a serialized object. (Furthermore, Laravel contains several gadget chains usable to trigger remote command execution from arbitrary deserialization.) Therefore, an attacker in possession of the APPKEY is able to fully control a string passed to an unserialize function.

Invoice Ninja version 3.8.1 is vulnerable to stored cross-site scripting vulnerability, within the invoice creation page, which can result in disruption of service and execution of javascript code.

In Invoice Ninja before 4.4.0, there is an unsafe call to unserialize() in app/Ninja/Repositories/AccountRepository.php that may allow an attacker to deserialize arbitrary PHP classes. In certain contexts, this can result in remote code execution. The attacker's input must be hosted at http://www.geoplugin.net (cleartext HTTP), and thus a successful attack requires spoofing that site or obtaining control of it.

invoiceninja is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')