How to check the latest patch version applied to magento?

I'm assuming you do have FTP access. When patches are applied a file named applied.patches.list is added in the app/etc/ directory.

Next to that the patch is nothing more than a diff file so you can see what it should change when you open it and check in the targeted file if it is indeed changed

You can test successful installation of the patches (and existence of other known vulnerabilities) at https://www.magereport.com (used to be at https://shoplift.byte.nl but I've extended the checks)

Simply use SSH to check if your shop is patched

For More information kindly visit below URL: https://support.hypernode.com/knowledgebase/how-to-apply-magento-patches/

You can scan your site with magereport.com to see if a patch is installed or not. If a check comes up grey it’s possible the files that are needed for the check are relocated. Therefore it can’t see whether your shop is patched or not. No worries. Simply use SSH to check if your shop is patched.

Every check that’s been installed can easily be found in the content of your shop. More specifically it’s logged in app/etc/applied.patches.list

So you run this command 'grep' on SSH to access the list of applied security patches:

grep '|' app/etc/applied.patches.list

The output will look like this:

-e 2015-04-14 08:34:22 UTC | SUPEE-5344 | EE_1.14.1.0 | v1 | a5c9abcb6a387aabd6b33ebcb79f6b7a97bbde77 | Thu Feb 5 19:14:49 2015 +0200 | v1.14.1.0..HEAD

Hope It's helpful for anyone.