CVE-2026-112374
Medium 4.3
Description
FOSSBilling before 0.8.9 contains a Cross-Site Request Forgery vulnerability in the staff guest login endpoint (POST /api/guest/staff/login) that allows remote attackers to force authentication because checkGuestClientAuthentication() only allowlists client_login and client_create, leaving staff_login without CSRF or Origin validation. Attackers can host an auto-submitting HTML form with attacker-controlled credentials to silently log a victim's browser into the attacker's staff account.
Metrics
- CVSS 3.1
-
4.3 (MEDIUM)
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N - CVSS 4.0
-
5.1 (MEDIUM)
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/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 - EPSS — exploit probability
- 0% (percentile: 7) as of 1 November 2026
- CWE
- CWE-352