OpenAI launched Daybreak on May 11, 2026, a cybersecurity initiative using GPT-5.5 and Codex Security. The program directly competes with Anthropic's Glasswing project, which uses the unreleased Claude Mythos Preview model.
Key facts
- Daybreak launched May 11, 2026.
- Uses GPT-5.5, GPT-5.5-Cyber, and Codex Security.
- Competes with Anthropic's Glasswing using Claude Mythos.
- Mozilla patched 271 Firefox vulnerabilities with Mythos.
- Partners: Cloudflare, Cisco, CrowdStrike, Palo Alto Networks, Oracle, Akamai.
OpenAI has launched Daybreak, a cybersecurity initiative that's clearly the company's competitor to Anthropic's Project Glasswing. If you'll recall, Glasswing uses Anthropic's unreleased AI model, Claude Mythos Preview, to provide its clients' cyber defense needs. It's been promising, so far: Mozilla revealed in April that Mythos helped it find and patch 271 vulnerabilities in the latest release of the Firefox browser. OpenAI says Daybreak uses its various AI models, including its specialized security agent Codex.
In its announcement, the company explained that Daybreak is built around the premise that cyber defense should be built into software from the start and not just revolve around finding and fixing vulnerabilities. Daybreak aims to prioritize high-impact issues and reduce hours of analysis to minutes, to generate and test patches within repositories and to send back results with audit-ready evidence to the clients' systems. In OpenAI's example, it asked Codex Security to scan a codebase, validate the highest-risk findings and fix them.
Daybreak will use GPT-5.5 for general purposes and GPT-5.5 with Trusted Access for Cyber for most defensive security workflows, including "secure code review, vulnerability triage, malware analysis, detection engineering and patch validation." It will also rely on GPT-5.5-Cyber for "preview access for specialized workflows, including authorized red teaming, penetration testing and controlled validation." OpenAI is already working with several partners under the initiative, including Cloudflare, Cisco, CrowdStrike, Palo Alto Networks, Oracle and Akamai.
The unique take: This is not just another security tool — it's a direct product-market battle between two AI labs, each betting their models can out-hunt the other's in enterprise security. OpenAI is leveraging its existing Codex agent and GPT-5.5 family, while Anthropic has the Mozilla validation win. The winner could lock in multi-year contracts with the same enterprises both labs are already selling LLMs to.
What to watch
Watch for the first public benchmark comparing Daybreak's vulnerability detection rate vs. Glasswing's — likely from a third-party audit or a partner case study in the next 90 days. Also track whether Mozilla or another major browser vendor switches from Mythos to Daybreak.
