I have this issue in Bionic. It was caused by pip using an old install of an obsolete cffi in ~/.local from a pip --user install, as explained (and diagnosed) here:
https://stackoverflow.com/q/54054263/507544 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1512792 Title: Pip crashes with cryptography/cffi/openssl error To manage notifications about this bug go to: https://bugs.launchpad.net/memcached/+bug/1512792/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs