FOSSBilling up to 0.7.x API Endpoint hide_version_public information disclosure

Summaryinfo

A vulnerability labeled as problematic has been found in FOSSBilling up to 0.7.x. Affected is an unknown function of the component API Endpoint. Executing a manipulation of the argument hide_version_public can lead to information disclosure. The identification of this vulnerability is CVE-2026-40495. The attack may be launched remotely. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in FOSSBilling up to 0.7.x. It has been declared as problematic. This vulnerability affects an unknown part of the component API Endpoint. The manipulation of the argument hide_version_public with an unknown input leads to a information disclosure vulnerability. The CWE definition for the vulnerability is CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. As an impact it is known to affect confidentiality. CVE summarizes:

FOSSBilling is a free, open-source billing and client management system. Versions prior to 0.8.0 leak the exact system version through asset cache buster parameters in HTML output, bypassing the `hide_version_public` security setting. The FOSSBilling version is embedded in the query string of every `` and `` tag generated by the `script_tag` and `stylesheet_tag` Twig filters. This information is visible to all visitors — including unauthenticated guests — on every page, regardless of whether the `hide_version_public` setting is enabled. The `X-FOSSBilling-Version` HTTP header and the `guest.system.version` API endpoint correctly honour the `hide_version_public` setting, but the asset cache buster parameters were overlooked. Knowledge of the exact FOSSBilling version makes it significantly easier for malicious actors to identify known vulnerabilities applicable to a given installation and craft targeted exploits. While not a direct vulnerability on its own, it undermines the intended protection offered by the `hide_version_public` setting and facilitates reconnaissance. Version 0.8.0 contains a patch. There is no practical workaround that removes the version from asset URLs without modifying source code.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-40495 since 04/13/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1592.

Upgrading to version 0.8.0 eliminates this vulnerability. The upgrade is hosted for download at github.com.

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Productinfo

Type

• Billing Software

Name

• FOSSBilling

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5
• 0.6
• 0.7

Website

• Product: https://github.com/FOSSBilling/FOSSBilling/

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