No legal action but fired for contributing to open source

> You should also have the freedom to make modifications and use them privately in your own work or play, without even mentioning that they exist. If you do publish your changes, you should not be required to notify anyone in particular, or in any particular way.

As written it wouldn't be open source either, because "when used commercially" is contrary to the "No Discrimination Against Fields of Endeavor" criterion at https://opensource.org/osd .

The issue here is that when your boss tells you not to publish company material publicly and you knowingly disobey you will likely get fired and, frankly, rightly so.