Scratch org is created without Alias and reports "Cannot read property 'timeout' of undefined."

I tried several things, and installing the pre-release fixed the issue. So I assume it's a bug that's already known and will be fixed with the next version of the CLI. In the meantime you can try to install the pre-release version: sfdx plugins:install salesforcedx@pre-release.

This has come up before when the salesforcedx plugin is relying on an updated version of @salesforce/core but, for some reason, there is an old version in the CLI node_modules.

Although installing salesforcedx@pre-release fixed this for you, that tag is no longer being updated now that v44 has moved to latest so you won't get any further updates. Instead, I would recommend updating to latest. sfdx plugins:uninstall salesforcedx to remove your pre-release version, then sfdx plugins:install salesforcedx (same as sfdx plugins:install salesforcedx@latest) to install off the latest tag. If you see the problem off latest, this would give us more information.

If you want to help us figure out why dependencies aren't getting updated, then you can uninstall pre-release, give the output for sfdx plugins --core and the contents of ~/.local/share/sfdx/client/node_modules/salesforce-alm/package.json.

Update:

Based on the feedback, installing and uninstalling salesforcedx fixes the problem. It is usually best to keep salesforcedx so you get the updated one bundled with the CLI releases that are autoupdated. If anyone gets the error and wants to post the request information above, we can continue to debug the issue.