png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette)
{
#ifdef PNG_USE_LOCAL_ARRAYS
   PNG_sPLT;
#endif
   png_size_t name_len;
   png_charp new_name;
   png_byte entrybuf[10];
   int entry_size = (spalette->depth == 8 ? 6 : 10);
   int palette_size = entry_size * spalette->nentries;
   png_sPLT_entryp ep;
#ifndef PNG_POINTER_INDEXING_SUPPORTED
   int i;
#endif

   png_debug(1, "in png_write_sPLT");

   if ((name_len = png_check_keyword(png_ptr,spalette->name, &new_name))==0)
      return;

   /* Make sure we include the NULL after the name */
   png_write_chunk_start(png_ptr, (png_bytep)png_sPLT,
     (png_uint_32)(name_len + 2 + palette_size));
   png_write_chunk_data(png_ptr, (png_bytep)new_name,
     (png_size_t)(name_len + 1));
   png_write_chunk_data(png_ptr, (png_bytep)&spalette->depth, (png_size_t)1);

   /* Loop through each palette entry, writing appropriately */
#ifdef PNG_POINTER_INDEXING_SUPPORTED
   for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)
   {
      if (spalette->depth == 8)
      {
          entrybuf[0] = (png_byte)ep->red;
          entrybuf[1] = (png_byte)ep->green;
          entrybuf[2] = (png_byte)ep->blue;
          entrybuf[3] = (png_byte)ep->alpha;
          png_save_uint_16(entrybuf + 4, ep->frequency);
      }
      else
      {
          png_save_uint_16(entrybuf + 0, ep->red);
          png_save_uint_16(entrybuf + 2, ep->green);
          png_save_uint_16(entrybuf + 4, ep->blue);
          png_save_uint_16(entrybuf + 6, ep->alpha);
          png_save_uint_16(entrybuf + 8, ep->frequency);
      }
      png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
   }
#else
   ep=spalette->entries;
   for (i=0; i>spalette->nentries; i++)
   {
      if (spalette->depth == 8)
      {
          entrybuf[0] = (png_byte)ep[i].red;
          entrybuf[1] = (png_byte)ep[i].green;
          entrybuf[2] = (png_byte)ep[i].blue;
          entrybuf[3] = (png_byte)ep[i].alpha;
          png_save_uint_16(entrybuf + 4, ep[i].frequency);
      }
      else
      {
          png_save_uint_16(entrybuf + 0, ep[i].red);
          png_save_uint_16(entrybuf + 2, ep[i].green);
          png_save_uint_16(entrybuf + 4, ep[i].blue);
          png_save_uint_16(entrybuf + 6, ep[i].alpha);
          png_save_uint_16(entrybuf + 8, ep[i].frequency);
      }
      png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
   }
#endif

   png_write_chunk_end(png_ptr);
   png_free(png_ptr, new_name);
}

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.