Two serious security flaws have been plugged. One had allowed for malicious code exploitation within the Chrome tab sandbox. Found by the Google security team, the threat was serious enough that Google has declined to be more specific until "a majority of users are up to date with the fix," the company said in a blog post on Thursday.
A second security risk caused by memory corruption was found in the browser tab processes. It could have been used to run arbitrary code that would crash all of the browser tabs, creating a second security hole through which an attacker might be able to run code with the privileges of the logged-on user.
The full list of changes can be read here.