src/libs/zbxmemory/memalloc.c : mem_bucket_by_size() code is following

static int mem_bucket_by_size(zbx_uint64_t size)

{ if (size < MEM_MIN_BUCKET_SIZE) return 0; if (size < MEM_MAX_BUCKET_SIZE) return (size - MEM_MIN_BUCKET_SIZE) >> 3; return MEM_BUCKET_COUNT - 1; }

It must be following, especially size over MEM_MAX_BUCKET_SIZE is critical bug.

static int mem_bucket_by_size(zbx_uint64_t size)

{ if (MEM_MIN_BUCKET_SIZE > size) return 0; if (MEM_MAX_BUCKET_SIZE < size) return (size - MEM_MIN_BUCKET_SIZE) >> 3; return MEM_BUCKET_COUNT - 1; }