The Opera web browser is based on Google’s Chromium ‘engine’ – the same core software that powers the Chrome browser. Aside: the Chromium browser engine is not to be confused with the other ‘Chromium’ – Google’s operating system, ChromiumOS. What is it with big corporations and confusing names?
Anyway… when Chrome gets a security fix, an Opera release with the same fix will soon follow. Opera 35.0.2066.82, announced on February 23, contains the same updated version of Chromium as Chrome 48.0.2564.116, which was released on February 18.
The Chromium security issue addressed in the latest versions of Opera and Chrome is CVE-2016-1629. The bug potentially allows attackers to bypass Same Origin Policy (SOP) measures that normally prevent scripts on other hosts from running.
If you use Chrome or Opera, or any other web browser based on the Chromium engine, you should update it as soon as possible. Chrome and Opera have self-updating features which can be triggered by navigating to their respective ‘About’ pages.