{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-33543: FOSSBilling: Authentication bypass allows unauthenticated administrator creation","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-33543","status":"final","version":"1","initial_release_date":"2026-06-24T21:01:16.544Z","current_release_date":"2026-06-24T21:01:16.544Z","revision_history":[{"date":"2026-06-24T21:01:16.544Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"FOSSBilling is a free, open-source billing and client management system. Versions 0.7.2 and prior expose a guest API endpoint, /api/guest/staff/create, intended for initial administrator bootstrap. Due to a flawed admin-existence check, the endpoint remains usable after an administrator already exists. The flawed guard check uses is_countable() on a value that returns a Model_Admin object or null rather than a countable type, causing the expression to always evaluate as true and bypass the intended protection. As a result, an attacker can reach the unprotected endpoint to create a new administrator account and immediately authenticate, gaining a fully privileged admin session even when an admin already exists. This issue has been fixed in version 0.8.0.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-33543 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-33543"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-33543"},{"category":"external","summary":"https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-28mh-j262-q49w","url":"https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-28mh-j262-q49w"},{"category":"external","summary":"https://github.com/FOSSBilling/FOSSBilling/releases/tag/0.8.0","url":"https://github.com/FOSSBilling/FOSSBilling/releases/tag/0.8.0"}]},"product_tree":{"branches":[{"category":"vendor","name":"FOSSBilling","branches":[{"category":"product_name","name":"FOSSBilling","branches":[{"category":"product_version","name":"< 0.8.0","product":{"name":"FOSSBilling FOSSBilling < 0.8.0","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:fossbilling:fossbilling:\\<_0.8.0:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-33543","title":"FOSSBilling: Authentication bypass allows unauthenticated administrator creation","notes":[{"category":"description","text":"FOSSBilling is a free, open-source billing and client management system. Versions 0.7.2 and prior expose a guest API endpoint, /api/guest/staff/create, intended for initial administrator bootstrap. Due to a flawed admin-existence check, the endpoint remains usable after an administrator already exists. The flawed guard check uses is_countable() on a value that returns a Model_Admin object or null rather than a countable type, causing the expression to always evaluate as true and bypass the intended protection. As a result, an attacker can reach the unprotected endpoint to create a new administrator account and immediately authenticate, gaining a fully privileged admin session even when an admin already exists. This issue has been fixed in version 0.8.0.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1"]},"scores":[{"cvss_v4":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","baseScore":9.3,"baseSeverity":"CRITICAL"},"products":["CSAFPID-1"]}],"remediations":[{"category":"none_available","details":"No fixed version is published yet. Monitor the upstream advisory.","product_ids":["CSAFPID-1"]}]}]}