A content management system allows someone to go in to the backend of a website and make changes. These changes often include adding new content or changing existing content, adding products or services that can be purchased, creating new users, extracting data from a newsletter sign up for example and making structural or layout changes to the website.
IF the content management system falls in to the wrong hands it can have catastrophic results. Your website content could be changed to include harmful links, misrepresentations or even deleted entirely. If accessed it could also mean that sensitive data such as customer email address, phone numbers and postal addresses are accessed and then sold on.
It is vital therefore, to ensure that your CMS is as secure as you can make it at all times. If using an off the shelf CMS system this often meaning carrying out regular issued updates and making sure that the link to your database is secure. If you are using a bespoke system then the programmer who is responsible for the maintenance of the software will need to go in and update the areas for you.