You can deal with them almost like hotfixes (or simply call a hotfix branch "bugfix branch"). Distinguishing between hotfixes and "less critical fixes" does not make a huge difference for the model, the branches and the assignment of version numbers, so I guess for the Gitflow inventors left that out for the sake of simplicity. The Gitflow model is complex enough as it is.
Note what you described ("branching from the current deployed master tag, applying the fixes and merge back to master and tag it with a new version") are exactly the same steps which are executed for a hotfix. Of course, I agree to Thomas Owens answer that there may be a difference in urgency and fact some of the bug fixing code may already exist in the development branch and hence should be cherry picked from there. The latter is usually not shown in the popular Gitflow diagrams.