This update for libpng16 fixes the following issues:
png_set_tRNS and png_set_PLTE can lead to arbitrary code
execution (bsc#1260754).1.6.40-150600.3.17.11.6.40-150600.3.17.11.6.40-150600.3.17.11.6.40-150600.3.17.11.6.40-150600.3.17.11.6.40-150600.3.17.11.6.40-150600.3.17.11.6.40-150600.3.17.1