In the Linux kernel, the following vulnerability has been resolved: ceph: reject export_targets ranks >= CEPH_MAX_MDS in mdsmap decode MDSMap export_targets entries are monitor controlled. check_new_map() uses each entry as a bit number in a fixed stack bitmap, so a rank outside the protocol namespace can make set_bit() write past the end of the array. Reject ranks outside CEPH_MAX_MDS while decoding the map. Do not validate against possible_max_rank here because maps may legitimately reference ranks beyond a temporarily reduced max_mds.
https://git.kernel.org/stable/c/aedc9053d909508a5f56c3f49f885fc030df4730
https://git.kernel.org/stable/c/96c3f5fbb0d5386e7111426f047f98cec4586674
https://git.kernel.org/stable/c/736adee11af36e407ed902264f8b2fb5cf94b62f
https://git.kernel.org/stable/c/4d298880f82c42383b36946bafde7ccf4d804c9b