Review reviewHigh

CVE-2026-53643

FOSSBilling

FOSSBilling is a free, open-source billing and client management system. Versions prior to 0.8.0 allow low-privileged staff accounts to perform unauthorized actions via admin API endpoints. The root cause is a combination of the `can_always_access` module flag (which grants all staff access to certain modules) and insufficient permission checks or unsafe parameter handling on individual endpoints. Version 0.8.0 contains a fix. Some workarounds are available. Restrict staff accounts to only those who need access to sensitive settings and/or use a reverse proxy or WAF to restrict access to th...

CVSS: 8.7
EPSS: 0.23%
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 probability0.23%

Technical severityCVSS 8.7

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:H/VI:H/VA:H/SC:N/SI:N/SA:N/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-200, CWE-639, CWE-862