CVE-2026-33543

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Source
https://cve.org/CVERecord?id=CVE-2026-33543
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33543.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-33543
Aliases
  • GHSA-28mh-j262-q49w
Published
2026-06-24T21:01:16.544Z
Modified
2026-07-15T01:49:05.579290522Z
Severity
  • 9.3 (Critical) CVSS_V4 - 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 CVSS Calculator
Summary
FOSSBilling: Authentication bypass allows unauthenticated administrator creation
Details

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 iscountable() on a value that returns a ModelAdmin 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.

Database specific 
{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-288",
        "CWE-306"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33543.json"
}
References

Affected packages

Git / github.com/fossbilling/fossbilling

Affected ranges

Type
GIT
Repo
https://github.com/fossbilling/fossbilling
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
3bd35f5b2921d8a26a403142ae0408f95e6463cc
Database specific 
{
    "source": [
        "AFFECTED_FIELD",
        "REFERENCES"
    ],
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "0.8.0"
        }
    ]
}

Affected versions

0.*
0.1.0
0.1.1
0.2.0
0.2.1
0.2.10
0.2.2
0.2.3
0.2.4
0.2.5
0.2.6
0.2.7
0.2.8
0.2.9
0.3.0
0.4.0
0.4.1
0.4.2
0.4.3
0.5.0
0.5.1
0.5.2
0.5.3
0.5.4
0.5.5
0.6.0
0.6.1
0.6.10
0.6.11
0.6.12
0.6.13
0.6.14
0.6.15
0.6.16
0.6.17
0.6.18
0.6.19
0.6.2
0.6.20
0.6.21
0.6.22
0.6.3
0.6.4
0.6.5
0.6.6
0.6.7
0.6.8
0.6.9
0.7.0
0.7.1
0.7.2

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33543.json"