After Sam Altman criticized Anthropic for limiting access to its cybersecurity tool, Mythos, by releasing it only to select users, he confirmed that OpenAI would take the same approach with its own competing tool, Cyber. In a post on X on Thursday, Altman announced that OpenAI will begin rolling out GPT-5.5 Cyber to critical cyber defenders in the coming days. OpenAI has an application on its website where individuals can submit information about their credentials and intended use to gain access.

According to the application, Cyber is capable of performing tasks such as penetration testing, vulnerability identification and exploitation, and malware reverse engineering. It is designed as a toolkit to help organizations identify security weaknesses and test their defenses. However, there are concerns that the tool could be misused by malicious actors.

When Anthropic similarly restricted access to Mythos, Altman dismissed the strategy as fear-based marketing. Some critics agreed, arguing that Anthropic's rhetoric was overblown. Ironically, an unauthorized group reportedly managed to access Mythos anyway. OpenAI has stated that it is working to make Cyber more widely available by consulting with the U.S. government and identifying additional users with legitimate cybersecurity credentials.