Source: https://www.todhost.com/knowledgebase/787/How-to-check-WordPress-version-using-cPanel.html

On very few occasions, we have attempted to recover some exploited WordPress websites. One easy way to get this done had been to overwrite the files and then after things work fine, we secure the site again for the client. For you to do this successfully, you need to identify the software version that as exploited in order not to use a wrong software version for overwrite and creating a problem.

To be able to do this successfully, you need to identify the software version you are running and have it implemented on your website. If you are able to login to your website backend, that should be easy but if you are unable to login to the backend, then you need to follow the rest of the tutorial to identify your WordPress website version.

Secondly, good server maintenance practice requires maintaining your Content Management System to run the latest updates of software version. This can be a problem in cases where there is an exploitation on your website such a White Screen of Death. Dealing with such situations will in most cases require file overwrite and you need to run the right version to recover the website before you implement an upgrade and take steps to secure your WordPress website. Here is a guide on how you can check your software version in cPanel.

Checking WordPress Versions

To confirm the 'latest' stable release of WordPress you can visit their official WordPress Download page. You should see something similar to: "The latest stable release of WordPress (Version X.X) is available in two formats from the links to your right." X.X being the latest version.

Ok, now "How do I know the versions of ALL my wordpress installs?"

• Default cPanel configurations:
o find /home/*/public_html/ -type f -iwholename "*/wp-includes/version.php" -exec grep -H "\$wp_version =" {} \;

This shows the location of the WordPress installation. /home/<CPANELUSER>/public_html/path and the version that's installed in that location.

If any of your WordPress installations are not using the most recent version of WordPress, it is very important to update it.

How to Manually Overwrite Your WordPress Files

Before you overwrite files please take note of the following:
• Delete the images folder so that all your image overwrite are retained. Except you have used custom image titles/names, you are most likely to loose the changes you made in your image folder after an override.
• Do not overwrite the logo. You can do this by deleting the logo file before you overwrite anything.
• Check any custom footer changes you made. Did you change or remove a copyright code, check in your new file before you overwrite the files.
• Check to protect any customizations you made to your files before you overwrite because you could loose all of them.

To manually overwrite your files, download the version of WordPress that you are currently running. Use an FTP software to overwrite the files. Once you do that successfully, immediately update to a most recent version that keeps you safe.

Final Advice: Always Maintain a Healthy Backup

If you keep a healthy backup, you can easily recover from a damage. Once you restore your website using your backup, you will need to take steps to protect your website from the exploitation or vulnerabilities that endangered your website. Always learn about your CMS vulnerabilities and how you can protect yourself from them.