The bug affects a few more libraries. I found that creating symlinks for all of them in /usr/lib/firefox/ is a workaround:
/usr/lib/x86_64-linux-gnu/libnssutil3.so /usr/lib/x86_64-linux-gnu/libnss3.so /usr/lib/x86_64-linux-gnu/libsmime3.so /usr/lib/x86_64-linux-gnu/libssl3.so
