8.4
HIGH CVSS 4.0
CVE-2026-111048
FOSSBilling: Low-privileged staff can run JavaScript in administrators' browsers via stored XSS in support ticket notes
Description

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.

INFO

Published Date :

Nov. 2, 2026, 6:18 p.m.

Last Modified :

Nov. 2, 2026, 6:18 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-111048 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 4.0 HIGH [email protected]
Solution
Update FOSSBilling to version 0.8.9 to fix stored XSS vulnerability in ticket notes.
  • Update FOSSBilling to version 0.8.9.
  • Sanitize all user-supplied input.
  • Avoid using innerHTML for rendering external content.
References to Advisories, Solutions, and Tools
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-111048 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-111048 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-111048 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-111048 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Nov. 02, 2026

    Action Type Old Value New Value
    Added Description 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.
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CWE CWE-79
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/111xxx/CVE-2026-111048.json">CVE-2026-111048</a>
    Added Reference https://github.com/FOSSBilling/FOSSBilling/commit/87528920b6cb1ba6f113583253eb4d7abdd1d8c6
    Added Reference https://github.com/FOSSBilling/FOSSBilling/pull/4548
    Added Reference https://github.com/FOSSBilling/FOSSBilling/releases/tag/0.8.9
    Added Reference https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-493h-fvcx-6q62
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.