Why are so many fresh zero-day vulnerabilities getting exploited in the wild?

A new study from Google says that last year, 41 new zero-day vulnerabilities were exploited in the wild. While that’s welcome news in terms of recent volume – it’s a 40% decrease from the all-time annual high of 69 in 2021 – it’s still well above the annual average compared to 2015 onward.

Zero-day vulnerabilities are dangerous because they allow attackers – who are oftentimes spies but sometimes criminals – to amass victims, frequently without the victims becoming aware until it’s too late. But simply counting the number of zero-day flaws that are found every year isn’t a guide to whether things are getting better or worse, and also cannot account for how many zero-day exploits are being used in the wild but haven’t yet been detected by the “good guys.”