--- title: Mythos found 271 Firefox flaws – none a human couldn’t spot description: Mozilla's CTO Bobby Holley shares results from testing Anthropic's Mythos AI model on Firefox security. Mythos found 271 vulnerabilities in Firefox 150, up... canonical: https://daily.dev/posts/mythos-found-271-firefox-flaws-none-a-human-couldn-t-spot-0erfxzsoo twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Mythos found 271 Firefox flaws – none a human couldn’t spot | daily.dev og:description: Mozilla's CTO Bobby Holley shares results from testing Anthropic's Mythos AI model on Firefox security. Mythos found 271 vulnerabilities in Firefox 150, up... og:url: https://daily.dev/posts/mythos-found-271-firefox-flaws-none-a-human-couldn-t-spot-0erfxzsoo og:image: https://api.daily.dev/og/posts/0ERFxzSOo.png og:image:alt: Mythos found 271 Firefox flaws – none a human couldn’t spot 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. # Mythos found 271 Firefox flaws – none a human couldn’t spot **[The Register](https://daily.dev/sources/theregister)** · 3 min read · 0 upvotes · 0 comments ## Summary Mozilla's CTO Bobby Holley shares results from testing Anthropic's Mythos AI model on Firefox security. Mythos found 271 vulnerabilities in Firefox 150, up from 22 found in an earlier test with Opus 4.6. Holley describes the results as a turning point for defenders, arguing that AI can now replicate the reasoning abilities of elite human security researchers at scale. Crucially, all bugs found were ones a human could also discover — no novel vulnerability classes emerged. He believes this closes the attacker-defender gap by making bug discovery cheap and widespread, rather than bottlenecked on scarce human expertise. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [The zero-days are numbered](https://daily.dev/posts/the-zero-days-are-numbered-hmbd9rmvz) · Mozilla · 8 upvotes · 2 comments --- Tags: [#anthropic](https://daily.dev/tags/anthropic), [#firefox](https://daily.dev/tags/firefox), [#ai-security](https://daily.dev/tags/ai-security) [View this post on daily.dev](https://daily.dev/posts/mythos-found-271-firefox-flaws-none-a-human-couldn-t-spot-0erfxzsoo) ```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":"Mythos found 271 Firefox flaws – none a human couldn’t spot","url":"https://daily.dev/posts/mythos-found-271-firefox-flaws-none-a-human-couldn-t-spot-0erfxzsoo","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/mythos-found-271-firefox-flaws-none-a-human-couldn-t-spot-0erfxzsoo"},"datePublished":"2026-04-22T04:35:15.407Z","dateModified":"2026-04-22T04:35:33.966Z","description":"Mozilla's CTO Bobby Holley shares results from testing Anthropic's Mythos AI model on Firefox security. 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