ChatGPT 5.x just tries to deny everything remotely cybersecurity-related - to the point that it would at times rather deny vulnerabilities exist than go poke at them. Unless you get real creative with prompting and basically jailbreak it. And it was this bad BEFORE they started messing around with 5.4 access specifically.
And that was ChatGPT 5.4. A model that, by all metrics and all vibes, doesn't even have a decisive advantage over Opus 4.6 - which just does whatever the fuck you want out of the box.
What's I'm afraid the most of is that Anthropic is going to snort whatever it is that OpenAI is high on, and lock down Mythos the way OpenAI is locking down everything.
Most AI for Cybersecurity companies use a mixture of models depending on iteration and testing, including OpenAI's.