Yes, but that’s not so much a problem with the language but more an issue of sentence construction. A big part of good communication in any language is anticipating that sort of ambiguity and adding context or rephrasing to remove it if required.
‘Can’t’ is really too passive to use if it really is ‘must not’ for anything serious, so while the sentence could work either way in spoken communication (because you can convey enough context with tone of voice and emphasis to imply which sense you mean), it would still not be a great choice of words if you mean the second sense.
‘Can’t’ is really too passive to use if it really is ‘must not’ for anything serious, so while the sentence could work either way in spoken communication (because you can convey enough context with tone of voice and emphasis to imply which sense you mean), it would still not be a great choice of words if you mean the second sense.