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Fencer Intel
high 8.7

CVE-2026-53643 json

FOSSBilling allows low-privileged staff accounts to perform unauthorized actions via admin API endpoints

published 4mo ago modified 4mo ago also EUVD-2026-41968

cvss
8.7
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 29%
public exploits
0
none known

Summary

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 the affected endpoints to trusted IP addresses or higher-privilege roles.

Patch / fix

  • fossbilling fossbilling 0.8.0

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
4mo ago

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 4.0 8.7 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
CNA 4.0 8.7 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

Affected products

  • FOSSBilling FOSSBilling

Classification

Weakness
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
  • CWE-639 Authorization Bypass Through User-Controlled Key
  • CWE-862 Missing Authorization

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.