Cotonti CSRF in PFS folder edit allows unauthorized folder modification

Cotonti 1.0.0 (master branch, commit f43f1fc3) is vulnerable to Cross-Site Request Forgery in the Personal File Storage (PFS) module. In modules/pfs/inc/pfs.editfolder.php, the folder update action ('a=update') updates folder metadata (title, description, public/gallery flags) without calling cot_check_xg() to validate the anti-CSRF token. A remote attacker who lures an authenticated user into visiting a malicious page can force the browser to submit a forged request that modifies the victim's folder metadata, including making a private folder public.