CVE intelligence and bounded remediation

CVE-2026-53644 — FOSSBilling is a free, open-source billing and client management system

High CVSS 8.6

FOSSBilling is a free, open-source billing and client management system. Versions 0.5.3 through 0.7.2 allow authenticated clients to both read and reset API key service secrets for orders that are no longer in an `active` state (e.g., `suspended`, `canceled`). The root cause is missing order-state validation in two client API endpoints, despite an `isActive()` helper already existing in the `Serviceapikey` module and the frontend UI correctly gating access on `order.status == 'active'`. Version 0.8.0 contains a fix. Some workarounds are available. If the `Serviceapikey` module is not needed, uninstall it to remove the affected endpoints. One may also use a reverse proxy or WAF to restrict access to `/api/client/order/service` and `/api/client/serviceapikey/reset` based on application-level order-state logic.

Severity
High
CVSS
8.6 (4.0)
Published
2026-07-06
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-639

Affected products

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Matched remediation archetype

Authorization bypass, IDOR, and cross-tenant access

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Check exposure

  • Map object and action authorization checks across API, UI, batch, import/export, and background-job paths.
  • Identify tenant, ownership, role, and policy boundaries for affected resources and administrative operations.
  • Use synthetic fixtures to compare intended access matrices without accessing another user's real data.

Remediate safely

  • Enforce server-side authorization at each resource access and state transition using the authenticated principal and trusted tenant context.
  • Scope data queries by tenant and ownership; treat client-supplied identifiers, roles, and policy claims as untrusted.
  • Add deny-by-default policy tests for horizontal and vertical access across every affected transport.

Authoritative sources

Complete CVE record and remediation plan

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