Canonical has a now made Ubuntu 17.10.1 available on its servers but is yet to list it on its main download page as of Saturday evening (GMT). The new ISO comes with the SPI kernel driver disabled in order to avoid damaging the BIOS on some computers. People have been unable to download the latest iteration of Ubuntu for the past three weeks while Canonical fixed the issue.
The re-spin comes just in time because, today, Ubuntu 17.04 has reached end of life, meaning that it will no longer receive updates. Due to this, users either have to move to Ubuntu 17.10 or do a clean install and downgrade to Ubuntu 16.04 until April when the next long-term release drops.
Aside from the main spin of Ubuntu, derivatives such as Xubuntu and Ubuntu MATE have also re-released their x86_64 ISOs on their respective websites. Once you finally reinstall Ubuntu 17.10, make sure you apply all of the latest updates in order to mitigate the Meltdown and Spectre vulnerabilities.
Ubuntu 17.10 will be supported by Canonical until July 2018, at which time updates will stop and you’ll have to upgrade. You can find the ISO here.