FOSSBilling up to 0.7.2 Config config.php prettyPrintArrayToPHP code injection

Summaryinfo

A vulnerability classified as problematic has been found in FOSSBilling up to 0.7.2. Impacted is the function Config::prettyPrintArrayToPHP of the file config.php of the component Config. Performing a manipulation results in code injection. This vulnerability is reported as CVE-2026-43921. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability was found in FOSSBilling up to 0.7.2. It has been classified as problematic. This affects the function Config::prettyPrintArrayToPHP of the file config.php of the component Config. The manipulation with an unknown input leads to a code injection vulnerability. CWE is classifying the issue as CWE-94. The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

FOSSBilling is a free, open-source billing and client management system. Versions 0.6.10 through 0.7.2 have a PHP code injection vulnerability in FOSSBilling's `Config::prettyPrintArrayToPHP()` method. When configuration values are updated, string values are written into `config.php` without escaping single quotes. Because `config.php` is loaded via a bare `include` on every HTTP request, an attacker with admin privileges can inject arbitrary PHP code that executes on every subsequent request. Version 0.8.0 contains a patch. Some workarounds are available. Restrict admin access to trusted personnel only; audit `config.php` for unexpected PHP code; and/ or at the reverse proxy/WAF level, restrict access to admin API endpoints that modify configuration.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-43921 since 05/04/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Additional levels of successful authentication are required for exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1059 for this issue.

By approaching the search of inurl:config.php it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 0.8.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-41961). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Billing Software

Name

• FOSSBilling

Version

• 0.7.0
• 0.7.1
• 0.7.2

Website

• Product: https://github.com/FOSSBilling/FOSSBilling/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Discussion