OpenAI releases GPT-5.5-Cyber for vetted security teams with relaxed safeguards

OpenAI released GPT-5.5-Cyber in limited preview on Thursday, a variant of its GPT-5.5 model with relaxed safeguards for vetted cybersecurity teams. The model follows Anthropic's Claude Mythos Preview release by one month.

Technical details

GPT-5.5-Cyber is based on the GPT-5.5 model OpenAI announced in late April. According to OpenAI, the cyber-specific version is "trained to be more permissive on security-related tasks" compared to the standard GPT-5.5 model.

The model targets three specific use cases:

• Vulnerability identification and triage
• Patch validation
• Malware analysis

OpenAI stated the preview "is not intended to be a major step up in terms of cyber capability" but rather removes safety constraints that would otherwise block security research workflows. The company said "GPT-5.5-Cyber lets a smaller set of partners study advanced workflows where specialized access behavior may matter."

Pricing and context window specifications were not disclosed. Access is restricted to vetted cybersecurity teams only.

Market context

The release comes one month after Anthropic's Claude Mythos Preview launch, which was distributed through Project Glasswing, a cybersecurity initiative limiting access to select companies. Anthropic CEO Dario Amodei met with Trump administration officials about Mythos, and Federal Reserve Chairman Jerome Powell and Treasury Secretary Scott Bessent discussed the model with major bank CEOs.

Anthropic faced Pentagon blacklisting weeks before the Mythos announcement, though the model still attracted significant government attention. Vice President JD Vance and Treasury Secretary Bessent held calls with tech CEOs ahead of Mythos's release.

What this means

Both OpenAI and Anthropic are now offering models with reduced safety guardrails to vetted partners, marking a shift toward specialized access tiers for sensitive security work. The limited release strategy suggests both companies are balancing the need for security research tools against risks of misuse. OpenAI's framing that this is "not a major step up in cyber capability" positions GPT-5.5-Cyber as an access control modification rather than a fundamentally more powerful model.