CVE-2026-27604
FOSSBilling: Improper API Role Validation (system) Enables Unauthenticated Access to Privileged Admin Functions
Description
FOSSBilling is a free, open-source billing and client management system. Starting in version 0.5.4 and prior to version 0.8.0, an authorization bypass in the API role handling allows unauthenticated access to privileged `/api/system/*` endpoints. Because `system` resolves to the cron admin identity, attackers can invoke admin API methods without valid credentials, session, or CSRF token. Version 0.8.0 patches the issue. Some workarounds are available. Block external access to `/api/system/*` at reverse proxy/WAF, restrict API access by trusted source IPs only (`api.allowed_ips`), rotate all admin/client API tokens immediately, invalidate active sessions and reset high-privilege credentials, and/or review API request logs for suspicious `/api/system/` access and treat as potential incident.
INFO
Published Date :
June 23, 2026, 2:25 p.m.
Last Modified :
June 23, 2026, 2:25 p.m.
Remotely Exploit :
No
Source :
GitHub_M
Affected Products
The following products are affected by CVE-2026-27604
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Update FOSSBilling to version 0.8.0 or later.
- Block external access to /api/system/*.
- Restrict API access by trusted IPs.
- Rotate API tokens and reset credentials.
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