3.4.3 is the latest stable of 3.4 series, and is also required for building Git version of LLVM.
cmake-3.4.3-1.fc23 has been submitted as an update to Fedora 23. https://bodhi.fedoraproject.org/updates/FEDORA-2016-d7f570536f
That was quick!
cmake-3.4.3-1.fc23 has been pushed to the Fedora 23 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2016-d7f570536f
cmake-3.4.3-1.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.