The pushdup function in util/decompile.c in libming through 0.4.8 does not recognize the need for ActionPushDuplicate to perform a deep copy when a String is at the top of the stack, making the library vulnerable to a util/decompile.c getName NULL pointer dereference, which may allow attackers to cause a denial of service via a crafted SWF file.
https://lists.debian.org/debian-lts-announce/2018/04/msg00008.html