---
id: 5172
title: "GPT-5.5: Mythos-Like Hacking, Open to All"
source_domain: xbow.com
source_url: "https://xbow.com/blog/mythos-like-hacking-open-to-all"
published_at: "2026-04-23T18:00:00Z"
tags: ["ai-security", "benchmark", "offensive-security", "vulnerability-detection", "gpt-5-5", "open-access"]
phying_url: "https://phying.com/item/5172"
lang: en
---

# GPT-5.5: Mythos-Like Hacking, Open to All

## Summary

XBOW's early access to GPT-5.5: the model cuts its vulnerability miss rate to 10% from GPT-5's 40%, a leap in black-box performance that effectively retires its white-box benchmark.

## Intelligence Metadata

- **Sources:** xbow.com
- **Published:** 2026-04-23T18:00:00Z
- **Original:** https://xbow.com/blog/mythos-like-hacking-open-to-all
- **Phying News:** https://phying.com/item/5172