Cotonti Siena 0.9.26 and earlier contains a stored cross-site scripting vulnerability that allows authenticated users with PFS access to inject arbitrary script payloads by supplying malicious HTML in the ntitle parameter processed through the TXT filter in pfs.main.php. Attackers can create a folder with a crafted title containing script tags that are stored unescaped in the database and execute in the browser of any user who views the folder listing, including administrators.