Comment 6 for bug 1854764

Sorry, wrong repository - please ignore the previous post (I was still using the broken package version)

Second attempt:

$ sudo add-apt-repository ppa:ubuntu-security-proposed/ppa
$ sudo apt-get update
$ sudo apt install intel-microcode
$ sudo reboot

$ sudo reboot

$ apt policy intel-microcode
intel-microcode:
  Installed: 3.20191115.1ubuntu0.18.04.2
  Candidate: 3.20191115.1ubuntu0.18.04.2
  Version table:
 *** 3.20191115.1ubuntu0.18.04.2 500
        500 http://ppa.launchpad.net/ubuntu-security-proposed/ppa/ubuntu bionic/main amd64 Packages
        100 /var/lib/dpkg/status
     3.20191115.1ubuntu0.18.04.1 500
        500 http://de.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu bionic-security/main amd64 Packages
     3.20180312.0~ubuntu18.04.1 500
        500 http://de.archive.ubuntu.com/ubuntu bionic/main amd64 Packages

==> the version in the Ubuntu Security Proposed PPA seems to be working fine.

Thanks!