# CVE-2026-111048: FOSSBilling stored XSS in support ticket notes

Source: https://junglewise.ai/threats/cve-2026-111048-fossbilling-is-an-open-source-billing-and-client-management  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-02. Updated: 2026-11-02  
License: CC BY 4.0 with a link back

CVE-2026-111048 · Severity: info · Published 2026-11-02

FOSSBilling is an open source billing and client management platform used by hosting and service companies. An attacker with staff access and support ticket permissions can inject malicious scripts into support ticket notes that execute when other staff members view those notes. The injected script runs with the viewer's full session permissions and can steal data, perform administrative actions, or compromise accounts of high-privilege users.

Technologies: [FOSSBilling](https://junglewise.ai/threats/technologies/fossbilling). Vendors: [FOSSBilling](https://junglewise.ai/threats/vendors/fossbilling).

## Quick answers

**Is CVE-2026-111048 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-111048 being exploited in the wild.

**How severe is CVE-2026-111048?** Informational severity, published 2 November 2026.

**Which products and versions are affected?** FOSSBilling 0.1.0 to 0.8.8.

**Is there a fix for CVE-2026-111048?** Yes: fixed in 0.8.9. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-111048 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-111048?** Check whether you run FOSSBilling at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 0.8.9

## Technical details

The admin/support/note_create endpoint accepts and stores the note parameter without HTML sanitization in the support_ticket_note table. The admin ticket list template renders stored notes via innerHTML, allowing stored cross-site scripting (XSS). A staff user with support.manage_tickets permission can craft JavaScript payloads that execute in the browser of any staff member viewing the ticket, with access to that viewer's session privileges, CSRF tokens, and ability to read client or invoice data. The fix sanitizes notes as plain text on storage and renders them as text nodes instead of innerHTML to prevent both new and previously stored XSS payloads.

## Affected products

- FOSSBilling FOSSBilling 0.1.0 to 0.8.8

## Timeline

- 2026-11-02: disclosed

## References

- [https://github.com/FOSSBilling/FOSSBilling/commit/87528920b6cb1ba6f113583253eb4d7abdd1d8c6](https://github.com/FOSSBilling/FOSSBilling/commit/87528920b6cb1ba6f113583253eb4d7abdd1d8c6)
- [https://github.com/FOSSBilling/FOSSBilling/pull/4548](https://github.com/FOSSBilling/FOSSBilling/pull/4548)

## Related threats

- [FOSSBilling CSRF vulnerability in staff guest login endpoint](https://junglewise.ai/threats/cve-2026-112374-fossbilling-before-0-8-9-contains-a-cross-site-request-forgery)
- [FOSSBilling email enumeration via guest signup endpoint](https://junglewise.ai/threats/cve-2026-111056-fossbilling-is-an-open-source-billing-and-client-management)
- [FOSSBilling path traversal in template_exists endpoint](https://junglewise.ai/threats/cve-2026-111053-fossbilling-is-an-open-source-billing-and-client-management)
- [FOSSBilling authorization bypass in extension configuration management](https://junglewise.ai/threats/cve-2026-111046-fossbilling-is-an-open-source-billing-and-client-management)
- [FOSSBilling file overwrite via filename collision in downloadable products](https://junglewise.ai/threats/cve-2026-53648-fossbilling-file-overwrite-via-filename-collision-in-downloadable)