---
id: CVE-2026-90918
title: >-
  Joomla! Core - [20260908] - Core - XSS in HTML Mail Templates in Joomla
  4.0.0-5.4.8, 6.0.0-6.1.3 - The mail template feature lacks an escaping
  mechanism, causing XSS vectors in multiple extensions.
summary: >-
  Joomla! Core - [20260908] - Core - XSS in HTML Mail Templates in Joomla
  4.0.0-5.4.8, 6.0.0-6.1.3 - The mail template feature lacks an escaping
  mechanism, causing XSS vectors in multiple extensions.
severity: medium
cvss: 6.9
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N'
cwe:
  - CWE-79
vendor: Joomla! Project
product: Joomla! CMS
affected:
  - joomla_cms 4.0.0-5.4.8
  - joomla_cms 6.0.0-6.1.3
published: '2026-09-29'
updated: '2026-09-29'
sourceUpdated: '2026-09-29T17:17:13.890'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90918'
references:
  - url: >-
      https://developer.joomla.org/security-centre/1088-20260908-core-xss-in-html-mail-templates.html
    label: security@joomla.org
  - url: 'https://www.joomla.org/'
    label: security@joomla.org
tags:
  - nvd
  - cve.org
cvssSource: cna
ingestedAt: '2026-09-29T17:41:02.209Z'
---

## Overview

Joomla! Core - [20260908] - Core - XSS in HTML Mail Templates in Joomla 4.0.0-5.4.8, 6.0.0-6.1.3 - The mail template feature lacks an escaping mechanism, causing XSS vectors in multiple extensions.

## Remediation

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