Apple Patches Worst Zero-Day Bug 'In Recent Memory" May 20, 2021 Compliance Compliance Twitter Photo: Apple There's one industry that has a particular knack for getting its hands on clever software vulnerabilities in macOS: the adware industry. That ability has been demonstrated once again as Apple today patched a zero-day vulnerability, CVE-2021-30657, that allows an attacker to effortlessly route around three critical anti-malware defenses in macOS: Notarization, Gatekeeper and File Quarantine. It was first discovered by Cedric Owens, a lead offensive security engineer with Twilio, who reported the bug to Apple. It has been patched in macOS 11.3, which was released on Monday.