Having CF does not disqualify you from donating, but lots of the things that come with CF do.
I was told that i could not donate because i'd had a lung infection within the last 3 months. Anemia/low vitamin levels are another common thing they don't allow. Medications could be an issue, but it depends on what you take.
I would think that you sign liablity forms before donating, so that would not be an issue.