A vulnerability, which was classified as problematic , has been found in OS4ED openSIS-Classic 9.3 . This issue affects some unknown processing of the file modules/messaging/SentMail.php of the component Messaging Module . The manipulation leads to authorization bypass. This vulnerability is referenced as CVE-2026-8406 . Remote exploitation of the attack is possible. No exploit is available. It is suggested to install a patch to address this issue.