OpenAI’s GPT-5.5-Cyber will outperform Mythos in bug detection by Q1 2027

Third-party testing suggests GPT-5.5-Cyber is roughly as powerful as Mythos, but OpenAI’s rapid iteration cycle and broader dataset access may give it an edge. Given Microsoft’s recent findings and the competitive landscape, GPT-5.5-Cyber is likely to surpass Mythos in bug detection rates by the end of Q1 2027.

Implied probability (Yes)

60%