Ninja Forms plugin for WordPress before 3.15.4 contains an incomplete server-side validation vulnerability that allows unauthenticated attackers to submit arbitrary values to Checkbox List, Multi-Select List, Image List, Country, and State fields because NF_Abstracts_List falls through to a validate() method that only checks required-field presence. Attackers can submit crafted formula payloads through the unauthenticated nf_ajax_submit endpoint that bypass CSV escaping applied only to Textbox and Textarea fields, resulting in CSV injection when an administrator downloads and opens the exported submissions file.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
Active
User action required
Impact Assessment
Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
None
No disruption
CVSS Vector v4.0