HTMLDoc v1.9.15 was discovered to contain a heap overflow via (write_header) /htmldoc/htmldoc/html.cxx:273.
https://github.com/michaelrsweet/htmldoc/issues/425
https://github.com/michaelrsweet/htmldoc/commit/ee778252faebb721afba5a081dd6ad7eaf20eef3
https://github.com/michaelrsweet/htmldoc/commit/a0014be47d614220db111b360fb6170ef6f3937e