"Pegasus takes advantage of so-called zero-day vulnerabilities of software running on mobile phones, meaning built-in flaws that not even developers and manufac

"Pegasus takes advantage of so-called zero-day vulnerabilities of software running on mobile phones, meaning built-in flaws that not even developers and manufacturers are aware of." Vulnerabilities, eh - 'flaws'? Or backdoors there by design? What's in a name?