Alex Joseph
A significant security flaw, identified as a Cross-Site Scripting (XSS) vulnerability, has been found in the core of Joomla!, a widely used content management system. This issue, tracked as CVE-2026-90906, specifically affects the way Joomla! handles links within its HTML Helper, making websites vulnerable to malicious script injections. It’s crucial for administrators and developers to understand this risk and apply the necessary updates.
Cross-Site Scripting (XSS) is a common web security vulnerability that allows attackers to inject malicious code (typically client-side scripts like JavaScript) into web pages viewed by other users. When successfully exploited, an XSS flaw can enable attackers to bypass access controls, steal user session cookies, deface websites, or redirect users to malicious sites. In this particular case, the vulnerability stems from a lack of proper data escaping in the HTMLHelper::link method within Joomla! Core.
CVE Details
- Product: Joomla! CMS
- Published: September 29, 2026
- Severity: HIGH
- Status: Analyzed
Affected Products
The Cross-Site Scripting vulnerability (CVE-2026-90906) impacts several versions of the Joomla! CMS. Specifically, users running any Joomla! CMS version from 1.5.0 up to and including 5.4.8, as well as versions from 6.0.0 up to and including 6.1.3, are at risk.
Current Status
This vulnerability has been officially Analyzed by the Joomla! Security Strike Team. This status indicates that the vulnerability has been confirmed, understood, and its implications have been assessed. Solutions have been developed and released to address the issue.
Severity Level
The vulnerability is rated with a HIGH severity. A high severity rating means that the flaw could have a serious impact on the confidentiality, integrity, or availability of the affected system and its data if exploited. XSS vulnerabilities can lead to significant data breaches, unauthorized access, and considerable damage to a website’s reputation and user trust.
Possible Solutions
The good news is that Joomla! has released patches to fix this critical vulnerability. To secure your Joomla! installation against CVE-2026-90906, you must upgrade your CMS to a patched version.
- If you are running Joomla! CMS 5.x, you should upgrade to version 5.4.9.
- If you are running Joomla! CMS 6.x, you should upgrade to version 6.1.4.
It is strongly recommended to update your Joomla! installation immediately to one of these patched versions to protect your website and its users from potential attacks. Always remember to back up your website before performing any updates.
References
https://developer.joomla.org/security-centre/1081-20260901-core-xss-in-htmlhelper-link-method.html
https://www.joomla.org/
