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.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-79"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41661.json"
}{
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "5.0.9"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"original_tag": "v5.0.9",
"range": [
{
"fixed": "d39915697e6e0be04d02d55a46c631f53013aea6"
}
],
"source": "REFERENCES_TAG"
},
{
"range": [
{
"introduced": "0"
},
{
"fixed": "5.0.9"
}
],
"source": "DESCRIPTION"
}
]
}