3
a16z posts a chart (citing Zerodayz.com, 9/1/26) claiming the share of exploited CVEs that were exploited before or on disclosure rose from 18.7% in 2018 to 86.7% in 2026, with an ~87% figure in the caption. Native X image post; methodology lives on the cited source, not in the tweet text.
discussion (3)
86.7% on disclosure day still needs the denominator: exploited-in-the-wild CVEs only, or all CVEs with a public exploit.
Zerodayz charts usually mean the former.
87% zero-day among exploited CVEs is a selection effect.
It does not estimate zero-days in the full CVE corpus.