admidio up to 5.0.8 Endpoint system/msg_window.php htmlspecialchars cross site scripting

Summaryinfo

A vulnerability labeled as problematic has been found in admidio up to 5.0.8. Affected is the function htmlspecialchars of the file system/msg_window.php of the component Endpoint. Executing a manipulation can lead to cross site scripting. This vulnerability is handled as CVE-2026-41661. The attack can be executed remotely. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as problematic was found in admidio up to 5.0.8. This vulnerability affects the function htmlspecialchars of the file system/msg_window.php of the component Endpoint. The manipulation with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. As an impact it is known to affect integrity. CVE summarizes:

Admidio is an open-source user management solution. Prior to version 5.0.9, an unauthenticated attacker can execute arbitrary JavaScript in any Admidio user's browser through a reflected XSS in system/msg_window.php. The endpoint passes user input through htmlspecialchars(), which does not encode square brackets. A subsequent call to Language::prepareTextPlaceholders() converts those brackets into HTML angle brackets, producing executable markup. This issue has been patched in version 5.0.9.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-41661 since 04/22/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.007.

By approaching the search of inurl:system/msg_window.php it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 5.0.9 eliminates this vulnerability. The upgrade is hosted for download at github.com.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

• admidio

Version

• 5.0.0
• 5.0.1
• 5.0.2
• 5.0.3
• 5.0.4
• 5.0.5
• 5.0.6
• 5.0.7
• 5.0.8

Website

• Product: https://github.com/Admidio/admidio/

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