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TI-2026-83050 Aliases CVE-2026-112374GHSA-595p-xmhc-mfxv

Login CSRF in FOSSBilling staff guest login API

Priority LOW 22CWE-352Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
Tampering
Confidentiality · integrity · availability
None · Low · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-352.

Summary

FOSSBilling from 0.1.0 before 0.8.9 contains a cross-site request forgery flaw in the staff guest login endpoint, tracked as CWE-352. The endpoint does not validate CSRF tokens or the Origin header, so a remote attacker can force a victim's browser to log in to the attacker's staff account. An attacker only needs to host an auto-submitting HTML form with attacker-controlled credentials and wait for a victim to visit the page.

Written with Claude Haiku 5.5 from the sources below · 2026-11-05

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00172 6th percentileScored 2026-11-07
Fix Fixed FOSSBilling (FOSSBilling): 0.8.9

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
FOSSBillingFOSSBilling0.1.0 to before 0.8.90.8.9Patch availableCNA
  • FOSSBilling VendorFOSSBilling Affected 0.1.0 to before 0.8.9 Fixed in 0.8.9 Patch available CNA

Remediation

Upgrade FOSSBilling to version 0.8.9 or later, which fixes the issue.

Written with Claude Haiku 5.5 from the sources below · 2026-11-05

  • Fix · CNA FOSSBilling (FOSSBilling) Fixed in 0.8.9

Timeline

  1. 2026-10-30 Threatist record created from CVE-2026-112374
  2. 2026-10-30 Alias added: GHSA-595p-xmhc-mfxv
  3. 2026-11-05 CISA SSVC decision points changed

References

Patch 1

Advisory 1

  • TI-2023-03258 SQL Injection in fossbilling/fossbilling CVSS 3.1CRITICAL 9.8
  • TI-2023-03719 Insufficient Session Expiration in fossbilling/fossbilling CVSS 3.1CRITICAL 9.8
  • TI-2023-03259 Unrestricted Upload of File with Dangerous Type in fossbilling/fossbilling CVSS 3.1HIGH 8.8
  • TI-2023-03261 Improper Neutralization of Formula Elements in a CSV File in fossbilling/fossbilling CVSS 3.1HIGH 8.0
  • TI-2026-30636 FOSSBilling missing authorization in guest Invoice API endpoints CVSS 4.0HIGH 7.7
  • TI-2023-03173 Code Injection in fossbilling/fossbilling CVSS 3.1HIGH 7.2
See all 43 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences