In Netwide Assembler (NASM) 2.14rc0, there is a "SEGV on unknown address" that will cause a remote denial of service attack, because asm/preproc.c mishandles macro calls that have the wrong number of arguments.
https://usn.ubuntu.com/3694-1/
http://repo.or.cz/nasm.git/commit/59ce1c67b16967c652765e62aa130b7e43f21dd4