Last week, we released Security Advisory 2015-01, with text suggesting that only specific platforms were seriously affected. We must now report that this was incorrect: all platforms are impacted. The advisory has been updated to that effect.
Furthermore, by popular demand, we have released Authoritative Server 3.3.2, an update to version 3.3.1 which includes DNSSEC improvements and of course a patch for the security issue. Click these links: release notes, tarball, debs, RPMs.