Got an email a while ago, went into my spam bucket. Not seeing this announcement on the site here (maybe I'm not looking in the right place? I checked the "blog" and it's not there either) but here's what the email says:
Today we released Genesis 1.8.1, a minor release that contains a fix for a possible security issue.
If you are currently running 1.8.0 or older, we recommend that you upgrade.
To upgrade, simply visit your WordPress dashboard:
1. Click the "upgrade now" link in the update notification at the top of your dashboard page.
2. Confirm the upgrade.
3. After the new version is installed, click the link to complete the upgrade.
4. That's it.... you'll then be running he [sic] latest version of Genesis.