OPNsense 19.1 contains multiple cross-site scripting vulnerabilities in the diagbackup.php endpoint that allow attackers to inject malicious scripts through multiple parameters including GDriveGDriveEmail, GDriveGDriveFolderID, GDriveGDriveBackupCount, Nextcloudurl, Nextclouduser, Nextcloudpassword, Nextcloudpasswordencryption, and Nextcloudbackupdir. Attackers can submit POST requests with script payloads in these parameters to execute arbitrary JavaScript in the context of authenticated administrator sessions.