CVE-2026-53640: FOSSBilling missing authorization checks on read-only admin API endpoints expose sensitive staff, client, and redirect data
FOSSBilling is a free, open-source billing and client management system. Prior to version 0.8.0, low-privileged staff accounts may read sensitive data via admin API endpoints that lack permission checks. While sibling write endpoints correctly enforce fine-grained permissions, the corresponding read endpoints have no authorization guards. Version 0.8.0 contains a fix. Some workarounds are available. Restrict staff accounts to only those who need access to sensitive data and/or use a reverse proxy or WAF to restrict access to the affected endpoints.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
FOSSBillingto a version that resolves this vulnerability.Fixed in 0.8.0 - Compensating control
Use a reverse proxy or WAF to restrict access to the affected read-only admin API endpoints that lack authorization checks.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-53640?
CVE-2026-53640 has a risk score of 47, indicating a moderate severity level due to missing authorization checks.
How do I fix CVE-2026-53640?
To fix CVE-2026-53640, upgrade your FOSSBilling installation to version 0.8.0 or later, which implements the necessary authorization checks.
What data is exposed due to CVE-2026-53640?
CVE-2026-53640 exposes sensitive staff, client, and redirect data to low-privileged staff accounts through admin API endpoints.
Which versions of FOSSBilling are affected by CVE-2026-53640?
CVE-2026-53640 affects all versions of FOSSBilling prior to version 0.8.0.
What type of vulnerability is CVE-2026-53640 classified as?
CVE-2026-53640 is classified as an information leakage vulnerability due to missing authorization checks.