Bitmap objects can be passed between processes by flattening them to a Parcel in one process and un-flattening them in another. In order to conserve memory, there exists a code path which allows Bitmaps to be shared between processes by providing an ashmem-mapped file descriptor containing the Bitmap’s raw pixel data. The android.graphics.Bitmap class illegally assumes that the size of the ashmem region provided by the user matches the actual underlying size of the Bitmap.