The wmem_block_split_free_chunk function in epan/wmem/wmem_allocator_block.c in the wmem block allocator in the memory manager in Wireshark 1.12.x before 1.12.7 does not properly consider a certain case of multiple realloc operations that restore a memory chunk to its original size, which allows remote attackers to cause a denial of service (incorrect free operation and application crash) via a crafted packet.