Review reviewHigh

CVE-2026-53645

FOSSBilling

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...

CVSS: 8.5
EPSS: 0.24%
CISA KEV: Not listed
Published: 2026.07.07

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.24%

Technical severityCVSS 8.5

Vulnerability overview

Affected product and versions

Product: FOSSBilling
Affected versions: < 0.8.0
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that FOSSBilling and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CWE: CWE-269