CVE-2026-90918 Joomla! Core - [20260908] - Core - XSS in HTML Mail Templates in Joomla 4.0.0-5.4.8, 6.0.0-6.1.3
Attackers can inject malicious scripts via HTML mail templates in Joomla, potentially leading to code execution or account takeover.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-90918?
CVE-2026-90918 is a medium-severity cross-site scripting vulnerability in Joomla Joomla\!, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-79
Which versions are affected by CVE-2026-90918?
1 open source package ship an affected version, including joomla. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
joomla Bitnami | From 4.0.0 | 5.4.8, 6.1.3 |
Products include Joomla Joomla\!.
How do I fix CVE-2026-90918?
Upgrade joomla to a fixed version for your release line: 5.4.8 or 6.1.3.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-90918 being exploited?
There is no known exploitation of CVE-2026-90918 in the wild and no public exploit code.
Other vulnerabilities in Joomla Joomla\!
- CVE-2016-10033 PHPMailer Command Injection
- CVE-2023-23752 Joomla! Improper Access Control
- CVE-2026-48902 Joomla! Core - [20260518] - Transport encryption downgrade for password and username reset links
- CVE-2025-25226 [20250401] - Joomla Framework - SQL injection vulnerability in quoteNameStr method of Database package
- CVE-2022-23795 [20220303] - Core - User row are not bound to a authentication mechanism
Sources
Also known as BIT-joomla-2026-90918, GHSA-gv72-vwwm-957f.