CVE-2026-41661

Admidio: Reflected XSS in msg_window.php via Square Bracket to HTML Tag Conversion

Published May 7, 2026 CVSS 3.1 · 6.1 Medium EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-gq27-fc8w-vcmp Admidio vulnerable to reflected XSS in msg_window.php via Square Bracket to HTML Tag Conversion
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Admidio
Admidio admidio
Vendors & Products Admidio
Admidio admidio
Type Values Removed Values Added
Description 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.
Title Admidio: Reflected XSS in msg_window.php via Square Bracket to HTML Tag Conversion
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 7, 2026, 2:58 PM
Reserved
Apr 21, 2026, 11:58 PM
Status
Deferred
Published
May 7, 2026, 4:16 AM
Modified
Jun 17, 2026, 10:46 AM