This is caused by the fact that updates to Firefox are published as security updates, and the default configuration is to automatically download and install security updates. Which is a sensible default for most users, but I agree can be disrupting in the case of a long running end-user application like Firefox.
An option is to open software-properties-gtk, go to the "Updates" tab, and change the value of the "When there are security updates" dropdown to something else than the default ("Download and install automatically"). This is not a bug in the firefox package itself. ** Changed in: firefox (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1964997 Title: Firefox updates uncontrollably To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1964997/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs