Mozilla released what appears to be a minor update to version 17.0.1. I'm not seeing any security updates. From the Release Notes:
17.0.1: Font rendering issue in Firefox 17.0 (bug 814101)
17.0.1: Reverted user agent change causing some website incompatibilities
Edit Note: I guess I didn't look far enough down the page. There were a few other fixes in version 17.0.1 as well as two new items. I'm not sure why the additional fixed items were listed at the bottom.
17.0.1: Leaving Private Browsing with Social API enabled should reset social components (814554)