If you use Adobe Acrobat DC and you’re on a Mac, you should update your software right now, because Adobe just pushed out a patch that fixes three critical vulnerabilities.

In its most recent update (version 20.009.20063), Adobe addressed a security issue that allowed local users to exploit Adobe Acrobat DC to gain root access to a macOS computer without being detected.

In a post on their personal blog, Tencent Security Xuanwu Lab researcher Yuebin Sun provided more background on the three vulnerabilities (CVE-2020-9615, CVE-2020-9614, CVE-2020-9613). Sun explains how, even with macOS’s built-in System Integrity Protection enabled, because a critical process in Acrobat runs as root instead of being sandboxed, it’s possible to use that flaw to gain system-level access to someone’s entire machine.

The software update adds a Protected Mode that sandboxes the app and “covers all the features and workflows in Acrobat.” Adobe says its new Protected Mode is a change to Acrobat’s core architecture and should address the app’s previous security concerns.

However, Protected Mode is turned off by default, so if you’re really concerned about security, you’ll need to take a few steps after updating Acrobat to the latest version. Open Acrobat, go to the Edit menu, select Preferences, and from the Categories section, select Security and click the checkbox that says Enable Protected Mode at Startup (Preview).

While any vulnerability that allows bad actors to gain root access to a system is quite serious, the upside of this is that a hacker would need physical access to your machine in order to exploit the flaw, so you don’t have to worry about someone gaining root access remotely.

The update includes a few other improvements, including a streamlined Fill & Sign experience and a simplified redaction tool, but the most important change is Protected Mode.

A lot of people turn to things like automatic updates and antivirus apps to protect their data, but it’s important not to overlook physical security as one of most basic steps for keeping your devices safe and sound.