CVE-2026-112374

FOSSBilling before 0.8.9 Login CSRF via Staff Guest Login API

MEDIUM
4.3
CVSS Score
Published: October 30, 2026 at 12:10 PM UTC
Updated: October 30, 2026 at 01:18 PM UTC
1 product affected across 1 vendorFOSSBilling

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Severity
MEDIUM4.3
Exploit prediction
EPSS 0.2%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

CVSS

4.3MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-352

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