Netwide Assembler (NASM) 2.14rc16 has a heap-based buffer over-read in expand_mmac_params in asm/preproc.c for the special cases of the % and $ and ! characters.
https://repo.or.cz/nasm.git/commit/4b5b737d4991578b1918303dc0fd9c9ab5c7ce4f
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00017.html
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00015.html