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TI-2026-38689 Aliases CVE-2026-53645

FOSSBilling's missing self-edit prevention in staff permission management allows persistent privilege escalation

Priority LOW 37CWE-269Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Privilege escalation
Confidentiality · integrity · availability
None · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-269.

Summary

FOSSBilling is a free, open-source billing and client management system. Versions prior to 0.8.0 allow a low-privileged staff account to grant arbitrary module permissions to itself through the admin API, resulting in persistent privilege escalation. A staff user that only has `staff.create_and_edit_staff` can call `/api/admin/staff/permissions_update` targeting their own account and write any permission structure, bypassing the intended role-based access control boundary. Version 0.8.0 patches the issue. Some workarounds are available. Restrict the `staff.create_and_edit_staff` permission to only highly trusted staff members and/or use a reverse proxy or WAF to restrict access to `/api/admin/staff/permissions_update` to specific trusted roles.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00372 31st percentileScored 2026-11-07
Fix Fixed FOSSBilling (FOSSBilling): 0.8.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
FOSSBillingFOSSBillingbefore 0.8.00.8.0Patch availableCNA
  • FOSSBilling VendorFOSSBilling Affected before 0.8.0 Fixed in 0.8.0 Patch available CNA

Remediation

  • Fix · CNA FOSSBilling (FOSSBilling) Fixed in 0.8.0

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-53645

References

Other 1

  • TI-2023-03258 SQL Injection in fossbilling/fossbilling CVSS 3.1CRITICAL 9.8
  • TI-2023-03719 Insufficient Session Expiration in fossbilling/fossbilling CVSS 3.1CRITICAL 9.8
  • TI-2023-03259 Unrestricted Upload of File with Dangerous Type in fossbilling/fossbilling CVSS 3.1HIGH 8.8
  • TI-2023-03261 Improper Neutralization of Formula Elements in a CSV File in fossbilling/fossbilling CVSS 3.1HIGH 8.0
  • TI-2026-30636 FOSSBilling missing authorization in guest Invoice API endpoints CVSS 4.0HIGH 7.7
  • TI-2023-03173 Code Injection in fossbilling/fossbilling CVSS 3.1HIGH 7.2
See all 43 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences