A stored cross-site scripting vulnerability in maintenance-appendcode-check.php in Revive Adserver 6.0.8 and earlier allows an authenticated manager to execute JavaScript in an administrator's browser. A manager can store a malicious tracker name and cause the tracker to appear in the append-code maintenance results. When an administrator opens the affected maintenance page, the tracker name is included in HTML without appropriate encoding. The issue is fixed in Revive Adserver 6.0.9 by HTML-encoding tracker names when displaying the maintenance results.