Researchers have found that in roughly 80% of cases, spikes in malicious activity like network reconnaissance, targeted scanning, and brute-forcing attempts targeting edge networking devices are a precursor to the disclosure of new security vulnerabilities (CVEs) within six weeks. [...]

https://www.bleepingcomputer.com/news/security/spikes-in-malicious-activity-precede-new-cves-in-80-percent-of-cases/