Wordpress Plugin EventON Calendar 4.4 - Unauthenticated Post Access via IDOR

# Exploit Title: Wordpress Plugin EventON Calendar 4.4 - Unauthenticated Post Access via IDOR
# Date: 03.08.2023
# Exploit Author: Miguel Santareno
# Vendor Homepage: https://www.myeventon.com/
# Version: 4.4
# Tested on: Google and Firefox latest version
# CVE : CVE-2023-3219

# 1. Description
The plugin does not validate that the event_id parameter in its eventon_ics_download ajax action is a valid Event, allowing unauthenticated visitors to access any Post (including unpublished or protected posts) content via the ics export functionality by providing the numeric id of the post.


# 2. Proof of Concept (PoC)
Proof of Concept:
https://example.com/wp-admin/admin-ajax.php?action=eventon_ics_download&event_id=<any post id>