CVE-2026-27708 FOSSBilling: IDOR in Servicecustom Client API allows cross-client data access
Authenticated clients can access other users' sensitive data by guessing order IDs due to missing ownership checks in the API.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-27708?
CVE-2026-27708 is a high-severity missing authorization vulnerability in FOSSBilling, published on 24 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
FOSSBilling is a free, open-source billing and client management system. In versions 0.7.2 and prior, the Servicecustom Client API's __call method accepts an order_id parameter and fetches the associated order without verifying the authenticated client owns it, potentially exposing cross-client data through IDOR. An authenticated client can access any other client's custom service by guessing sequential order IDs. This can lead to a confidentiality breach — attackers can read client PII (name, email, phone, address, company details, VAT number) and service configuration data belonging to other clients. This issue has been fixed in version 0.8.0.
Which versions are affected by CVE-2026-27708?
How do I fix CVE-2026-27708?
No fix has been published for CVE-2026-27708 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-27708 being exploited?
There is no known exploitation of CVE-2026-27708 in the wild and no public exploit code.
Sources
Also known as GHSA-p36w-9x66-488j.