{"id":"CVE-2026-41661","aliases":["GHSA-gq27-fc8w-vcmp"],"url":"https://o3.security/vulnerability/CVE-2026-41661","summary":"Admidio: Reflected XSS in msg_window.php via Square Bracket to HTML Tag Conversion","details":"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.","published":"2026-05-07T02:59:34.649Z","modified":"2026-08-07T11:51:04.248375258Z","cvss":{"score":6.1,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"admidio/admidio","fixedVersion":"5.0.9"}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/Admidio/admidio/releases/tag/v5.0.9"},{"type":"ADVISORY","url":"https://github.com/Admidio/admidio/security/advisories/GHSA-gq27-fc8w-vcmp"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41661.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-41661"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:51:04.248375258Z"}}