Our evaluation of OpenAI's GPT-5.5 cyber capabilities

Simon Willison's Blog Models

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Simon Willison evaluates OpenAI's GPT-5.5 cyber capabilities, examining its performance in cybersecurity tasks.

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# Our evaluation of OpenAI’s GPT-5.5 cyber capabilities Source: [https://simonwillison.net/2026/Apr/30/gpt-55-cyber-capabilities/](https://simonwillison.net/2026/Apr/30/gpt-55-cyber-capabilities/) This is a**link post**by Simon Willison, posted on[30th April 2026](https://simonwillison.net/2026/Apr/30/)\. [ai2008](https://simonwillison.net/tags/ai/)[openai417](https://simonwillison.net/tags/openai/)[generative\-ai1779](https://simonwillison.net/tags/generative-ai/)[llms1745](https://simonwillison.net/tags/llms/)[anthropic282](https://simonwillison.net/tags/anthropic/)[claude275](https://simonwillison.net/tags/claude/)[ai\-security\-research17](https://simonwillison.net/tags/ai-security-research/)[gpt124](https://simonwillison.net/tags/gpt/) ### Monthly briefing Sponsor me for**$10/month**and get a curated email digest of the month's most important LLM developments\. Pay me to send you less\! [Sponsor & subscribe](https://github.com/sponsors/simonw/)

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