Executive brief
FOSSBilling, an open-source billing and client management platform, contains a vulnerability that allows an administrator to take full control of the underlying server. By saving specially crafted configuration settings, an attacker can inject malicious code that runs automatically every time the application is accessed. This could lead to the theft of sensitive customer data, complete service disruption, or the use of the server for further attacks.
Technical details
A PHP code injection vulnerability exists in the `Config::prettyPrintArrayToPHP()` method of FOSSBilling. The root cause is a failure to escape single quotes when writing user-supplied configuration strings into the `config.php` file. An attacker with administrative privileges can use API endpoints like `set_interface_ip()` to inject arbitrary PHP code into the configuration file. Because `config.php` is loaded via a bare `include` statement on every HTTP request, the injected code executes with the privileges of the web server user. The vulnerability is patched in version 0.8.0.
Affected products
- FOSSBilling FOSSBilling 0.6.10 - 0.7.2
Timeline
- 2026-06-12: advisory: GitHub advisory published
- 2026-07-06: disclosed: NVD publication date