Is CVE-2026-27604 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-27604 being exploited in the wild.

How severe is CVE-2026-27604?

Informational severity, with a CVSS score of 10, published 23 June 2026.

Which products and versions are affected?

FOSSBilling FOSSBilling >= 0.5.4, < 0.8.0.

Is there a fix for CVE-2026-27604?

A patch was published on 2026-05-28: Version 0.8.0 released with fixes Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-27604 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-27604?

Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-27604: FOSSBilling authorization bypass in system API endpoints

Q: Is there a fix for CVE-2026-27604?

A patch was published on 2026-05-28: Version 0.8.0 released with fixes Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-27604 attacked?

It is attacked over the network, in a network appliance.

Q: Am I affected by CVE-2026-27604?

Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-27604 · Severity: info · CVSS 10 · Published 2026-06-23

FOSSBilling is an open-source platform used by hosting providers to manage client billing and service provisioning. A security flaw allows anyone on the internet to bypass login requirements and access administrative functions without a password. An attacker could use this to steal customer data, modify billing records, or take full control of the server, potentially leading to a total service outage and data breach.

Quick answers

Is CVE-2026-27604 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-27604 being exploited in the wild.
How severe is CVE-2026-27604?: Informational severity, with a CVSS score of 10, published 23 June 2026.
Which products and versions are affected?: FOSSBilling FOSSBilling >= 0.5.4, < 0.8.0.
Is there a fix for CVE-2026-27604?: A patch was published on 2026-05-28: Version 0.8.0 released with fixes Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-27604 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-27604?: Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An authorization bypass exists in the API role handling logic within FOSSBilling. The root cause is a logic error where an exception for disallowed roles is instantiated but never thrown, allowing the 'system' role to proceed. Because the 'system' role resolves to the 'cron admin' identity, unauthenticated attackers can invoke administrative API methods under `/api/system/*` without valid credentials, sessions, or CSRF tokens. This can be further chained with a Server-Side Template Injection (SSTI) vulnerability in the Twig rendering engine to achieve unauthenticated Remote Code Execution (RCE). The issue is patched in version 0.8.0.

Affected products

FOSSBilling FOSSBilling >= 0.5.4, < 0.8.0

Timeline

2026-06-20: advisory: Initial GitHub security advisory published
2026-05-28: patched: Version 0.8.0 released with fixes
2026-06-23: disclosed: NVD publication and public blog disclosure

References

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