[TestMethod]
public void TestMethod()
{
    var cultureInfo = Mock.Create<CultureInfo>();
    var thisThrowsAnException = cultureInfo.Name;
}

One of the possible workarounds is to create a mock like this:

readonly string cultureName = CultureInfo.InvariantCulture.Name;
...
var cultureInfo = Mock.Create(() => new CultureInfo(cultureName));