---
id: CVE-2026-85190
title: >-
  Joomla Extension - regularlabs.com - Privileged stored XSS via class option in
  Quick Index extension for Joomla < 5.0.5 - Quick Index inserts configurable
  class values into generated HTML without escaping them for an HTML attribute
summary: >-
  Joomla Extension - regularlabs.com - Privileged stored XSS via class option in
  Quick Index extension for Joomla < 5.0.5 - Quick Index inserts configurable
  class values into generated HTML without escaping them for an HTML attribute.
  A cr…
severity: high
cvss: 7.5
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/S:N/AU:N'
cwe:
  - CWE-79
vendor: regularlabs.com
product: plg_system_quickindex
affected:
  - plg_system_quickindex 1.0.0-5.0.4
published: '2026-09-14'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T19:28:06.713'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-85190'
references:
  - url: 'https://www.regularlabs.com/'
    label: security@joomla.org
tags:
  - nvd
  - cve.org
epss: 0.00418
epssPercentile: 0.33426
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-14T11:32:05.952147Z'
cvssSource: cna
ingestedAt: '2026-09-14T15:23:07.453Z'
---

## Overview

Joomla Extension - regularlabs.com - Privileged stored XSS via class option in Quick Index extension for Joomla < 5.0.5 - Quick Index inserts configurable class values into generated HTML without escaping them for an HTML attribute. A crafted value can close the intended class attribute and introduce a new attribute. Joomla's content filter cannot reliably prevent this because Quick Index creates the executable HTML after the authored plugin syntax was filtered.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.