{"id":3048,"date":"2026-05-13T11:04:10","date_gmt":"2026-05-13T11:04:10","guid":{"rendered":"https:\/\/blog.ibvl.in\/index.php\/2026\/05\/13\/openais-gpt-5-5-is-as-good-as-mythos-at-finding-security-vulnerabilities\/"},"modified":"2026-05-13T11:04:10","modified_gmt":"2026-05-13T11:04:10","slug":"openais-gpt-5-5-is-as-good-as-mythos-at-finding-security-vulnerabilities","status":"publish","type":"post","link":"https:\/\/blog.ibvl.in\/index.php\/2026\/05\/13\/openais-gpt-5-5-is-as-good-as-mythos-at-finding-security-vulnerabilities\/","title":{"rendered":"OpenAI\u2019s GPT-5.5 is as Good as Mythos at Finding Security Vulnerabilities"},"content":{"rendered":"<div>\n<p>The UK\u2019s AI Security Institute evaluated GPT-5.5\u2019s ability to find security vulnerabilities, and <a href=\"https:\/\/www.aisi.gov.uk\/blog\/our-evaluation-of-openais-gpt-5-5-cyber-capabilities\">found<\/a> that it is comparable to Claude Mythos. Note that the OpenAI model is generally available.<\/p>\n<p><a href=\"https:\/\/www.aisi.gov.uk\/blog\/our-evaluation-of-claude-mythos-previews-cyber-capabilities\">Here<\/a> is the Institute\u2019s evaluation of Mythos.<\/p>\n<p>And <a href=\"https:\/\/aisle.com\/blog\/ai-cybersecurity-after-mythos-the-jagged-frontier\">here<\/a> is an analysis of a smaller, cheaper model. It requires more scaffolding from the prompter, but it is also just as good.<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>The UK\u2019s AI Security Institute evaluated GPT-5.5\u2019s ability to find security vulnerabilities, and found that it is comparable to Claude Mythos. Note that the OpenAI model is generally available. Here is the Institute\u2019s evaluation of Mythos. And here is an analysis of a smaller, cheaper model. It requires more scaffolding from the prompter, but it [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-container-style":"default","site-container-layout":"default","site-sidebar-layout":"default","disable-article-header":"default","disable-site-header":"default","disable-site-footer":"default","disable-content-area-spacing":"default","footnotes":""},"categories":[4,90,53,242],"tags":[91],"class_list":["post-3048","post","type-post","status-publish","format-standard","hentry","category-ai","category-cybersecurity","category-uncategorized","category-vulnerabilities","tag-cybersecurity"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v26.7 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>OpenAI\u2019s GPT-5.5 is as Good as Mythos at Finding Security Vulnerabilities - Imperative Business Ventures Limited<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/blog.ibvl.in\/index.php\/2026\/05\/13\/openais-gpt-5-5-is-as-good-as-mythos-at-finding-security-vulnerabilities\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"OpenAI\u2019s GPT-5.5 is as Good as Mythos at Finding Security Vulnerabilities - Imperative Business Ventures Limited\" \/>\n<meta property=\"og:description\" content=\"The UK\u2019s AI Security Institute evaluated GPT-5.5\u2019s ability to find security vulnerabilities, and found that it is comparable to Claude Mythos. Note that the OpenAI model is generally available. Here is the Institute\u2019s evaluation of Mythos. And here is an analysis of a smaller, cheaper model. It requires more scaffolding from the prompter, but it [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/blog.ibvl.in\/index.php\/2026\/05\/13\/openais-gpt-5-5-is-as-good-as-mythos-at-finding-security-vulnerabilities\/\" \/>\n<meta property=\"og:site_name\" content=\"Imperative Business Ventures Limited\" \/>\n<meta property=\"article:published_time\" content=\"2026-05-13T11:04:10+00:00\" \/>\n<meta name=\"author\" content=\"admin\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"admin\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/blog.ibvl.in\/index.php\/2026\/05\/13\/openais-gpt-5-5-is-as-good-as-mythos-at-finding-security-vulnerabilities\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/blog.ibvl.in\/index.php\/2026\/05\/13\/openais-gpt-5-5-is-as-good-as-mythos-at-finding-security-vulnerabilities\/\"},\"author\":{\"name\":\"admin\",\"@id\":\"https:\/\/blog.ibvl.in\/#\/schema\/person\/55b87b72a56b1bbe9295fe5ef7a20b02\"},\"headline\":\"OpenAI\u2019s GPT-5.5 is as Good as Mythos at Finding Security Vulnerabilities\",\"datePublished\":\"2026-05-13T11:04:10+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/blog.ibvl.in\/index.php\/2026\/05\/13\/openais-gpt-5-5-is-as-good-as-mythos-at-finding-security-vulnerabilities\/\"},\"wordCount\":75,\"keywords\":[\"Cybersecurity\"],\"articleSection\":{\"0\":\"AI\",\"1\":\"Cybersecurity\",\"3\":\"Vulnerabilities\"},\"inLanguage\":\"en-US\"},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/blog.ibvl.in\/index.php\/2026\/05\/13\/openais-gpt-5-5-is-as-good-as-mythos-at-finding-security-vulnerabilities\/\",\"url\":\"https:\/\/blog.ibvl.in\/index.php\/2026\/05\/13\/openais-gpt-5-5-is-as-good-as-mythos-at-finding-security-vulnerabilities\/\",\"name\":\"OpenAI\u2019s GPT-5.5 is as Good as Mythos at Finding Security Vulnerabilities - 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