Mac users will want to update to the latest version of Mac OS as soon as possible.
The update patches a security flaw that allows hackers to secretly take screenshots of your computer screen.
The malware XCSSET was first uncovered last year by security researchers at Trend Micro. Using this malware, bad actors would target Mac developers and infect those apps at the source. Unaware that their code had been compromised, developers would then distribute the app to users, infecting them with the malware in the process.