--- title: After dissing Anthropic for limiting Mythos, OpenAI... description: OpenAI is restricting access to its cybersecurity AI tool GPT-5.5 Cyber, rolling it out only to vetted 'critical cyber defenders' — the same approach Sam... canonical: https://daily.dev/posts/after-dissing-anthropic-for-limiting-mythos-openai-restricts-access-to-cyber-too-lyahl57t8 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: After dissing Anthropic for limiting Mythos, OpenAI restricts access to Cyber, too | daily.dev og:description: OpenAI is restricting access to its cybersecurity AI tool GPT-5.5 Cyber, rolling it out only to vetted 'critical cyber defenders' — the same approach Sam... og:url: https://daily.dev/posts/after-dissing-anthropic-for-limiting-mythos-openai-restricts-access-to-cyber-too-lyahl57t8 og:image: https://api.daily.dev/og/posts/lyahL57T8.png og:image:alt: After dissing Anthropic for limiting Mythos, OpenAI restricts access to Cyber, too og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # After dissing Anthropic for limiting Mythos, OpenAI restricts access to Cyber, too **[TechCrunch](https://daily.dev/sources/tc)** · 1 min read · 0 upvotes · 0 comments ## Summary OpenAI is restricting access to its cybersecurity AI tool GPT-5.5 Cyber, rolling it out only to vetted 'critical cyber defenders' — the same approach Sam Altman previously mocked Anthropic for taking with its competing tool Mythos. Cyber is capable of penetration testing, vulnerability identification, exploitation, and malware reverse engineering. OpenAI is working with the U.S. government to expand access to credentialed users. The irony is compounded by reports that an unauthorized group had already gained access to Anthropic's restricted Mythos tool. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Anthropic’s Mythos is moving between governments faster than regulators](https://daily.dev/posts/anthropic-s-mythos-is-moving-between-governments-faster-than-regulators-fnrfssbic) · The Next Web · 0 upvotes · 0 comments - [“A successful attack could be catastrophic”: Anthropic gives more groups access to Claude Mythos](https://daily.dev/posts/a-successful-attack-could-be-catastrophic-anthropic-gives-more-groups-access-to-claude-mythos-c5rinn0vq) · The New Stack · 0 upvotes · 0 comments - [Unauthorized group has gained access to Anthropic’s exclusive cyber tool Mythos, report claims](https://daily.dev/posts/unauthorized-group-has-gained-access-to-anthropic-s-exclusive-cyber-tool-mythos-report-claims-oow35kcqe) · TechCrunch · 31 upvotes · 17 comments - [Microsoft taps Anthropic’s Mythos to strengthen secure software development](https://daily.dev/posts/microsoft-taps-anthropic-s-mythos-to-strengthen-secure-software-development-jfpxuscls) · CSO Online · 0 upvotes · 0 comments --- Tags: [#security](https://daily.dev/tags/security), [#cyber](https://daily.dev/tags/cyber), [#openai](https://daily.dev/tags/openai), [#anthropic](https://daily.dev/tags/anthropic), [#ai-safety](https://daily.dev/tags/ai-safety) [View this post on daily.dev](https://daily.dev/posts/after-dissing-anthropic-for-limiting-mythos-openai-restricts-access-to-cyber-too-lyahl57t8) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"After dissing Anthropic for limiting Mythos, OpenAI restricts access to Cyber, too","url":"https://daily.dev/posts/after-dissing-anthropic-for-limiting-mythos-openai-restricts-access-to-cyber-too-lyahl57t8","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/after-dissing-anthropic-for-limiting-mythos-openai-restricts-access-to-cyber-too-lyahl57t8"},"datePublished":"2026-04-30T19:30:39.278Z","dateModified":"2026-04-30T19:35:04.636Z","description":"OpenAI is restricting access to its cybersecurity AI tool GPT-5.5 Cyber, rolling it out only to vetted 'critical cyber defenders' — the same approach Sam...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/cdc1fcfee2f0c95e6d4df6dfcd59781b?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/cdc1fcfee2f0c95e6d4df6dfcd59781b?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"TechCrunch","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"TechCrunch","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/tc","url":"https://daily.dev/sources/tc"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/after-dissing-anthropic-for-limiting-mythos-openai-restricts-access-to-cyber-too-lyahl57t8","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"security,cyber,openai,anthropic,ai-safety","timeRequired":"PT1M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"TechCrunch","item":"https://daily.dev/sources/tc"},{"@type":"ListItem","position":3,"name":"After dissing Anthropic for limiting Mythos, OpenAI restricts access to Cyber, too"}]} ```