---
id: "CVE-2026-107903"
kind: "vulnerability"
aliases: ["CVE-2026-107903"]
title: "Gridbox Joomla extension: stored XSS in reviews via weak sanitization"
severity: "high"
cvss: 8.6
epss: null
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["balbooa", "gridbox", "joomla", "other", "self-hosted"]
not_affected_if: ["gridbox-not-installed", "reviews-disabled"]
published_at: "2026-11-05T18:17:00+00:00"
first_seen_at: "2026-11-05T18:40:09+00:00"
updated_at: "2026-11-05T18:40:20+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-107903", "first_seen_at": "2026-11-05T18:40:09+00:00"}]
exploit_sources: []
---

# Gridbox Joomla extension: stored XSS in reviews via weak sanitization

Gridbox, a Joomla extension from balbooa.com, stores review content without consistent sanitization, so a malicious review can carry script. The script runs in the browser of anyone who views the review, which can lead to session theft or actions taken as that user.

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

## How to check

- Check the installed Gridbox version in the Joomla extensions manager (unknown beyond that).
- Confirm whether the reviews feature is enabled on the site.

## Fix

- Gridbox versions below `2.20.5.0` are affected; move to `2.20.5.0` or later.

## Timeline

- 2026-11-05T18:40:09+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-107903

## From the sources

Joomla Extension - balbooa.com - Stored XSS in reviews via inconsistent sanitization in Gridbox < 2.20.5.0

---

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