I understand your worries as they were one of my reasons to join these government organized briefings.

It seems very unlikely that such a lib in itself has any cyber security risk as long as it itself does not query an external database through a network connection.

The users of the lib have to asses that it has no security risk.

Did you sign any formal agreement with the users of the lib? Is there still any obligsation on your side with respect to the lib?

If you would discover some security issue, like a buffer overrun, would you fix it? Then just mentioning it, would be enough. The users of the lib bear the greatest responsibility. They have to regularly check your lib for security problems.