static void FilterRows(uint8* ybuf, const uint8* y0_ptr, const uint8* y1_ptr,
                       int source_width, int source_y_fraction) {
  __m128i zero = _mm_setzero_si128();
  __m128i y1_fraction = _mm_set1_epi16(source_y_fraction);
  __m128i y0_fraction = _mm_set1_epi16(256 - source_y_fraction);

  const __m128i* y0_ptr128 = reinterpret_cast<const __m128i*>(y0_ptr);
  const __m128i* y1_ptr128 = reinterpret_cast<const __m128i*>(y1_ptr);
  __m128i* dest128 = reinterpret_cast<__m128i*>(ybuf);
  __m128i* end128 = reinterpret_cast<__m128i*>(ybuf + source_width);

  do {
    __m128i y0 = _mm_loadu_si128(y0_ptr128);
    __m128i y1 = _mm_loadu_si128(y1_ptr128);
    __m128i y2 = _mm_unpackhi_epi8(y0, zero);
    __m128i y3 = _mm_unpackhi_epi8(y1, zero);
    y0 = _mm_unpacklo_epi8(y0, zero);
    y1 = _mm_unpacklo_epi8(y1, zero);
    y0 = _mm_mullo_epi16(y0, y0_fraction);
    y1 = _mm_mullo_epi16(y1, y1_fraction);
    y2 = _mm_mullo_epi16(y2, y0_fraction);
    y3 = _mm_mullo_epi16(y3, y1_fraction);
    y0 = _mm_add_epi16(y0, y1);
    y2 = _mm_add_epi16(y2, y3);
    y0 = _mm_srli_epi16(y0, 8);
    y2 = _mm_srli_epi16(y2, 8);
    y0 = _mm_packus_epi16(y0, y2);
    *dest128++ = y0;
    ++y0_ptr128;
    ++y1_ptr128;
  } while (dest128 < end128);
}

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.