OpenAI Releases GPT-5.5-Cyber Preview for Vetted Security Teams
OpenAI has begun a limited preview of GPT-5.5-Cyber, a more permissive version of its latest model, for vetted cybersecurity teams. The rollout follows Anthropic's Claude Mythos Preview by one month and includes details on intended security workflows.

The model is not positioned as a major advance in raw cyber capability. Instead, OpenAI said it was trained to be more permissive on security-related tasks than the generally available GPT-5.5 version released late last month.
Vetted teams can use the preview for workflows including vulnerability identification and triage, patch validation, and malware analysis. The standard safeguards in GPT-5.5 would have restricted these activities, the company noted.
"GPT-5.5-Cyber lets a smaller set of partners study advanced workflows where specialized access behavior may matter," OpenAI stated in its blog post.
The move comes one month after Anthropic launched Claude Mythos Preview and restricted access to a select group of companies under its Project Glasswing cybersecurity initiative.
Anthropic CEO Dario Amodei met with senior Trump administration officials to discuss Mythos after the company had been blacklisted by the Pentagon weeks earlier. Federal Reserve Chairman Jerome Powell and Treasury Secretary Scott Bessent also met with major U.S. bank CEOs about the model, while Vice President JD Vance and Bessent held a call with leading tech CEOs ahead of its release.
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