Apple has issued security updates for OS X Yosemite, OS X El Capitan and Safari to address a vulnerability called “Pegasus” that potentially allows nefarious agents to take over a target device with a single click. You can download the updates via the Mac App Store — and you certainly should.
As noted by AppleInsider, Pegasus leverages three zero-day vulnerabilities to remotely jailbreak and install a suite of monitoring software onto a victim's device. One of the key tools in the process is an exploit that takes advantage of a memory corruption flaw in Safari WebKit. The vulnerability allows attackers to deliver the malware payload when a target clicks on a link leading to a malicious webpage.