A well secured Linux computer, especially when behind a robust firewall would probably not be easy to compromise, if at all. An well secured OpenBSD system is

A well secured Linux computer, especially when behind a robust firewall would probably not be easy to compromise, if at all. An well secured OpenBSD system is likely to be even more resilient. Since Linux is used by Android and shipped as many different distros, in a general sense, there probably are a multitude of security holes. IoT devices are even more of a concern. The problems with these Linux deployments is not with Linux kernel nor GNU utilities per se, but with the insecure configuration and poorly written apps. You are probably referring to (almost-)fake news articles, by sloppy journalists. They rarely research properly their topics, nor do they provide suitable caveats. Sensationalism wins the day for them.