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CVE-2026-111056

FOSSBilling: Unauthenticated client account enumeration via guest signup endpoint PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
FOSSBilling / FOSSBillingaffected >= 0.1.0, < 0.8.7

CWE

CWE-200, CWE-204, CWE-307

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.