High-severity CVE disclosures spiked 3.5× after Claude Mythos Preview launch

New serious vulnerabilities spiked around release of Claude Mythos Preview

Epoch AI reports that major orgs disclosed ~1,500 high- and critical-severity CVEs in June 2026, over 3.5× the pre-Mythos monthly record. Anthropic had announced in April that Claude Mythos Preview can autonomously find software bugs; its Project Glasswing claims 10,000+ high/critical finds, many still undisclosed individually. OpenAI's Daybreak is doing similar work. The post doesn't break down how many of the June disclosures were model-found vs. previously backlogged.

Why it matters: Epoch AI lays out the correlation between Mythos release and CVE spike with hard numbers—3.5× is concrete. Deduction because this is correlation, not causal proof, and the post doesn't break down vulnerability types.