CVE-2026-111056

FOSSBilling is an open source billing and client-management platform. From 0.1.0 until 0.8.7, the unauthenticated POST /api/guest/client/create endpoint reveals whether a submitted email belongs to a registered client because guest signup returns a distinct unredacted error when the submitted email already exists. The trigger is an unauthenticated request to POST /api/guest/client/create with a target email address. An attacker can compare the guest-signup response for a target email to determine whether the email belongs to an existing FOSSBilling client. Box\Mod\Client\Api\Guest::create returns the error after Client\Service::clientAlreadyExists finds a matching record, and the API response exposes that exception message without redaction. This issue is fixed in version 0.8.7.

CVSS

No CVSS.

References

Link	Resource
https://github.com/FOSSBilling/FOSSBilling/commit/19f41ff0a45874c7362b7732c8f68db84bc59c55
https://github.com/FOSSBilling/FOSSBilling/pull/4234
https://github.com/FOSSBilling/FOSSBilling/releases/tag/0.8.7
https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-x4mh-g4pc-wfc5

Configurations

No configuration.

History

19 Oct 2026, 16:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-19 16:17

Updated : 2026-10-22 04:17

NVD link : CVE-2026-111056

Mitre link : CVE-2026-111056

CVE.ORG link : CVE-2026-111056

JSON object : View

Products Affected

No product.

CWE

CWE-200

Exposure of Sensitive Information to an Unauthorized Actor

CWE-204

Observable Response Discrepancy

CWE-307

Improper Restriction of Excessive Authentication Attempts

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