In GNU Libextractor 1.4, there is a heap-based buffer overflow in the EXTRACTOR_png_extract_method function in plugins/png_extractor.c, related to processiTXt and stndup.
https://lists.debian.org/debian-lts-announce/2017/12/msg00000.html
https://ftp.gnu.org/gnu/libextractor/libextractor-1.6.tar.gz