Executive brief
Froxlor is an open-source server management panel used to administer web hosting environments. A security flaw allows customers with FTP access to bypass administrative restrictions and assign themselves a full system command shell (such as /bin/bash) even when the administrator has restricted them to limited options. This allows a low-privileged user to gain interactive access to the underlying server, potentially leading to data theft, service disruption, or further attacks on the hosting infrastructure.
Technical details
An incorrect authorization vulnerability exists in Froxlor 2.3.6 due to missing server-side validation of the shell parameter in the Ftps.add and Ftps.update API handlers. While the web interface restricts shell selection based on the 'system.available_shells' configuration, the backend only performs generic string validation and does not check the input against the administrator-defined whitelist. In deployments using the default 'nssextrausers' integration, an authenticated customer with shell delegation enabled can submit a request with an arbitrary shell (e.g., /bin/bash). This value is then propagated by a root-owned cron task into the system's passwd database, granting the attacker interactive shell access to the host. The issue is resolved in version 2.3.7.
Affected products
- Froxlor Froxlor 2.3.6
Timeline
- 2026-05-15: patched: Version 2.3.7 released
- 2026-05-29: advisory: GitHub Security Advisory published
- 2026-06-04: disclosed: CVE published to NVD