A double free when handling responses in read_file in tools/egk-tool.c (aka the eGK card tool) in OpenSC before 0.19.0-rc1 could be used by attackers able to supply crafted smartcards to cause a denial of service (application crash) or possibly have unspecified other impact.
https://www.x41-dsec.de/lab/advisories/x41-2018-002-OpenSC/
https://lists.debian.org/debian-lts-announce/2019/09/msg00009.html