Improper Access Check in Joomla Media File Overwrite

Executive Summary

CVE-2026-48947 is a security vulnerability in Joomla! CMS versions 4.1.0 through 5.4.6 and 6.0.0 through 6.1.1. It involves incorrect access control in the com_media webservice endpoints.

This flaw allows privileged users to overwrite media files without having the proper editing permissions, meaning that users with certain privileges can bypass restrictions that should prevent them from modifying media files.

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Detection Guidance

This vulnerability involves incorrect access control in the com_media webservice endpoints of Joomla! CMS, allowing privileged users to overwrite media files without proper editing permissions.

To detect this vulnerability on your system, you should first verify the Joomla! CMS version in use. Versions 4.1.0 through 5.4.6 and 6.0.0 through 6.1.1 are affected.

A practical detection step is to check the version of Joomla! installed by running a command or inspecting the version.php file typically located in the Joomla! root directory.

• Use a command like: `grep 'public $release' path/to/joomla/version.php` to find the version string.
• Alternatively, access the Joomla! administrator backend and check the version information displayed.

Since the vulnerability is related to access control on the com_media webservice endpoints, monitoring or logging attempts to overwrite media files without proper permissions could help detect exploitation attempts.

No specific network commands or scanning tools are provided in the available resources to detect exploitation attempts directly.

The recommended mitigation is to upgrade Joomla! to versions 5.4.7 or 6.1.2 where the vulnerability is fixed.

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Impact Analysis

This vulnerability can lead to unauthorized modification of media files by privileged users who should not have editing rights.

Such unauthorized overwriting of media files could result in content tampering, potential defacement, or the introduction of malicious files, which may affect the integrity and trustworthiness of the website.

Although the impact is considered moderate, the severity and probability are low.

To mitigate this risk, users are advised to upgrade to Joomla! versions 5.4.7 or 6.1.2 where the issue has been fixed.

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Compliance Impact

The provided information does not specify how this vulnerability affects compliance with common standards and regulations such as GDPR or HIPAA.

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Mitigation Strategies

To mitigate this vulnerability, users should upgrade Joomla! CMS to versions 5.4.7 or 6.1.2 or later.

This update fixes the incorrect access control in the com_media webservice endpoints that allowed privileged users to overwrite media files without proper editing permissions.

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