---
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: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N'
cwe:
  - CWE-79
vendor: joomla
product: joomla!
affected:
  - 'joomla! >= 4.0.0, < 5.4.8'
  - 'joomla! >= 6.0.0, < 6.1.3'
patched:
  - joomla! 6.1.3
published: '2026-09-29'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T16:35:27.190'
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
epss: 0.00202
epssPercentile: 0.10036
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-30T15:10:23.798690Z'
scores:
  nvd: 5.3
  cna: 6.9
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.

## Affected

- `joomla! >= 4.0.0, < 5.4.8`
- `joomla! >= 6.0.0, < 6.1.3`

## Remediation

Upgrade past the affected range:

- `joomla! 6.1.3`