{
  "$type": "site.standard.document",
  "bskyPostRef": {
    "cid": "bafyreigrml5all3elg2ci7ilxga64n575uwfgorlm75rot25de74n6nv3i",
    "uri": "at://did:plc:kyxdufbi5qaljy7bxivztuhy/app.bsky.feed.post/3mlrufv7tcdd2"
  },
  "path": "/blog/archives/2026/05/openais-gpt-5-5-is-as-good-as-mythos-at-finding-security-vulnerabilities.html",
  "publishedAt": "2026-05-13T11:03:03.000Z",
  "site": "https://www.schneier.com",
  "tags": [
    "Uncategorized",
    "AI",
    "cybersecurity",
    "vulnerabilities",
    "found",
    "Here",
    "here"
  ],
  "textContent": "The UK’s AI Security Institute evaluated GPT-5.5’s ability to find security vulnerabilities, and found that it is comparable to Claude Mythos. Note that the OpenAI model is generally available.\n\nHere is the Institute’s evaluation of Mythos.\n\nAnd here is an analysis of a smaller, cheaper model. It requires more scaffolding from the prompter, but it is also just as good.",
  "title": "OpenAI’s GPT-5.5 is as Good as Mythos at Finding Security Vulnerabilities"
}