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TI-2026-83925 Aliases CVE-2026-111048

Stored cross-site scripting in FOSSBilling support ticket notes

Priority LOW 38CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Active
Attack complexity
Low
Attack requirements
None
Impact type
Cross-site scripting
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

FOSSBilling from 0.1.0 before 0.8.9 does not sanitize support ticket notes submitted through the admin/support/note_create endpoint. The admin ticket list renders these stored notes through innerHTML, which is a cross-site scripting flaw (CWE-79). A staff user with only the support.manage_tickets permission can store script that runs in the browser of another staff member who opens the ticket notes, with that viewer's session and privileges, including a Super Administrator.

Written with Claude Haiku 5.5 from the sources below · 2026-11-03

Description from the CNA

FOSSBilling is an open source billing and client-management platform. From 0.1.0 until 0.8.9, the admin/support/note_create endpoint stores the note parameter without sanitization in the support_ticket_note table, and src/modules/Support/templates/admin/mod_support_tickets.html.twig renders each stored support ticket note through innerHTML in the admin ticket list. A staff user with only the support.manage_tickets permission can store HTML or JavaScript that executes when another staff member opens the ticket notes. The script runs with the viewing staff member's session and privileges, can read a CSRF token and accessible client or invoice data, and can perform administrative actions available to the viewer, including a Super Administrator. The ticket detail page is not affected because its Twig rendering uses autoescaping. This issue is fixed in version 0.8.9.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00278 20th 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
Total

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.

Written with Claude Haiku 5.5 from the sources below · 2026-11-03

  • Fix · CNA FOSSBilling (FOSSBilling) Fixed in 0.8.9

Timeline

  1. 2026-11-02 Threatist record created from CVE-2026-111048
  2. 2026-11-03 CISA SSVC decision points changed
  3. 2026-11-03 Priority changed: MEDIUM → LOW

References

Other 4

  • 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