299Ko's public contact form (plugin/contact/controllers/ContactController.php, home) sets raw POST field values (name, firstname, email, message) into the page template with no sanitization. The template engine's variable output function (common/Template.php, _show_var) echoes values with no htmlspecialchars call, and the sink template (contact.tpl) outputs these values unescaped into an HTML attribute and a textarea.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
Required
User action required
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
Low
Partial data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
Vulnerable Products
299ko:299ko