Five Eyes intelligence alliance warns of urgent cyber risks from new AI models on 23 June 2026

Key facts

• The Five Eyes intelligence alliance, comprising the United States, United Kingdom, Canada, Australia, and New Zealand, warned that frontier AI models will fundamentally transform offensive and defensive cyber capabilities.
• The alliance stated that the timeline for these AI-driven cyber threats is measured in months rather than years.
• AI models identified as potentially allowing users to execute complex hacks include Anthropic's Mythos and OpenAI's GPT-5.5-Cyber.
• The United States government ordered Anthropic to suspend access to its models for foreign nationals due to national security concerns, leading to the disabling of a version of Mythos.
• The Cybersecurity and Infrastructure Security Agency (CISA) reduced the deadline for government officials to address serious digital vulnerabilities in their networks to three days.