Quick answers
- Is CVE-2026-43921 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-43921 being exploited in the wild.
- How severe is CVE-2026-43921?
- Informational severity, with a CVSS score of 8.9, published 6 July 2026.
- Which products and versions are affected?
- FOSSBilling 0.6.10 - 0.7.2.
- Is there a fix for CVE-2026-43921?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-43921 attacked?
- It is attacked over the network, in a network appliance.
- Am I affected by CVE-2026-43921?
- Check whether you run FOSSBilling at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
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