This update for libpng16 fixes the following issues:
png_combine_row triggered via png_image_finish_read (bsc#1254160)png_image_read_composite (bsc#1254480)png_write_image_8bit with 8-bit input and convert_to_8bit enabled (bsc#1254158)png_image_read_composite via incorrect palette premultiplication (bsc#1254159)png_do_quantize via malformed palette index (bsc#1254157)1.6.40-150600.3.3.11.6.40-150600.3.3.11.6.40-150600.3.3.11.6.40-150600.3.3.11.6.40-150600.3.3.11.6.40-150600.3.3.11.6.40-150600.3.3.11.6.40-150600.3.3.1