CVE-2026-53645: Fossbilling

High severity, CVSS 8.5. EPSS: 0.4% chance of exploitation in the next 30 days.

FOSSBilling is a free, open-source billing and client management system. Versions prior to 0.8.0 allow a low-privileged staff account to grant arbitrary module permissions to itself through the admin API, resulting in persistent privilege escalation. A staff user that only has `staff.create_and_edit_staff` can call `/api/admin/staff/permissions_update` targeting their own account and write any permission structure, bypassing the intended role-based access control boundary. Version 0.8.0 patches the issue. Some workarounds are available. Restrict the `staff.create_and_edit_staff` permission to only highly trusted staff members and/or use a reverse proxy or WAF to restrict access to `/api/admin/staff/permissions_update` to specific trusted roles.

Affected products

• Fossbilling Fossbilling: before 0.8.0 (fixed in 0.8.0)

Published 2026-07-06. Last modified 2026-07-07.