Anthropic's Mythos AI finds 90 critical SharePoint bugs in April

Anthropic’s AI model Mythos is uncovering software vulnerabilities in Microsoft products faster than the company can fix them, according to a recording of an internal Microsoft meeting and documents reviewed by ProPublica. In April alone, Mythos found 90 critical and 141 important bugs in SharePoint, with even more discovered in the first half of May. By mid-May, most of the hundreds of critical and important bugs found across Microsoft 365, Teams, and Copilot remained unpatched. Microsoft is prioritizing the most dangerous flaws, but experts warn that unpatched lower-severity bugs could be chained together to create high-severity threats. The company acknowledged a sense of urgency but stood by its triage approach, saying it considers exploitability and customer impact. The flood of bugs has already led to record patch releases, including over 600 fixes on July 14, 2026, which one security expert called a "bug apocalypse."