---
id: "CVE-2026-111048"
kind: "vulnerability"
aliases: ["CVE-2026-111048"]
title: "FOSSBilling: stored XSS in support ticket notes hits admins"
severity: "high"
cvss: 8.4
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["billing", "fossbilling", "package", "self-hosted"]
not_affected_if: ["no-staff-ticket-access", "version-0.8.9-or-later"]
published_at: "2026-11-02T18:18:35+00:00"
first_seen_at: "2026-11-02T18:24:24+00:00"
updated_at: "2026-11-02T18:24:34+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-111048", "first_seen_at": "2026-11-02T18:24:24+00:00"}]
---

# FOSSBilling: stored XSS in support ticket notes hits admins

FOSSBilling stores support ticket notes without sanitizing them and renders them as raw HTML in the admin ticket list. A staff member with only ticket permissions can plant a script that runs in the session of another staff member, including a Super Administrator, and perform actions as them.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed FOSSBilling version and whether it is below `0.8.9`.
- Look at `src/modules/Support/templates/admin/mod_support_tickets.html.twig` for ticket notes rendered through `innerHTML`.

## Fix

- FOSSBilling: move to version `0.8.9`.

## Timeline

- 2026-11-02T18:24:24+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-111048

## Documents

- [advisory] Vendor advisory: github.com https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-493h-fvcx-6q62
- [fix] Patch: github.com https://github.com/FOSSBilling/FOSSBilling/commit/87528920b6cb1ba6f113583253eb4d7abdd1d8c6
- [fix] Release notes: github.com https://github.com/FOSSBilling/FOSSBilling/releases/tag/0.8.9

## From the sources

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.

---

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