Unauthenticated administrator creation via faulty existence check
Published Jun 24, 2026 · Updated Jun 24, 2026
Authentication bypass in FOSSBilling 0.7.2 and earlier allows remote attackers to create an administrator account through a guest API. The /api/guest/staff/create guard applies is_countable() to a Model_Admin object or null, so its negated check always admits the request. No credentials or interaction are required; default installations grant the resulting account full administrative access.
Summary
What happened
Authentication bypass in FOSSBilling 0.7.2 and earlier allows remote attackers to create an administrator account through a guest API. The /api/guest/staff/create guard applies is_countable() to a Model_Admin object or null, so its negated check always admits the request. No credentials or interaction are required; default installations grant the resulting account full administrative access.
The record
- CVE
- CVE-2026-33543
- Published
- Jun 24, 2026
- Updated
- Jun 24, 2026
- Vendor
- FOSSBilling
- Product
- FOSSBilling
- Classifications
- CWE-306, CWE-288, T1136
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 24, 2026CVE publishedPublication date reported by the CVE source.
- Jun 24, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 0.8.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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