medium6.1
CVE-2026-41661
Admidio vulnerable to reflected XSS in msg_window.php via Square Bracket to HTML Tag Conversion
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| composer | admidio/admidio | <= 5.0.8 | 5.0.9 |