CVE-2026-23513: FOSSBilling: Broken Authorization in Client Transaction and Order Listings

FOSSBilling is a free, open-source billing and client management system. In versions 0.7.2 and prior, a query-construction flaw in client list endpoints allowed authenticated clients to bypass tenant scoping and retrieve other clients’ data. Details In ServiceTransaction::getSearchQuery() and Order\Service::getSearchQuery(), OR-based search/action filters were appended without grouping, allowing SQL operator precedence to evaluate OR clauses independently of the enforced client_id constraint. Crafted requests could therefore return records and metadata belonging to other clients, including identifiers, amounts, status, timestamps, and related fields. This issue was fixed in version 0.8.0.