static HuffReader *get_huffman_group(WebPContext *s, ImageContext *img,
                                     int x, int y)
{
    ImageContext *gimg = &s->image[IMAGE_ROLE_ENTROPY];
    int group = 0;

    if (gimg->size_reduction > 0) {
        int group_x = x >> gimg->size_reduction;
        int group_y = y >> gimg->size_reduction;
        int g0      = GET_PIXEL_COMP(gimg->frame, group_x, group_y, 1);
        int g1      = GET_PIXEL_COMP(gimg->frame, group_x, group_y, 2);
        group       = g0 << 8 | g1;
    }

    return &img->huffman_groups[group * HUFFMAN_CODES_PER_META_CODE];
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.