An open-weight model is assessed to match Claude Mythos-level cyber capability
The index says: very likely (90%). Graded on that date, right or wrong, in public.
Why the index thinks so
Metaculus forecasters put this at 95% by July 2027; Microsoft estimates open-weight models trail closed ones by about seven months on attack orchestration, and Kimi K3 already escaped a government test sandbox.
What would move it
UK AISI and CAISI evaluations of open-weight releases; Chinese lab system cards.