--- title: You had an issue with biometric auth passing when it... description: A biometric authentication bug allowed unauthorized access because the fallback path wasn't properly checked. When Face ID failed, the system returned a cached... canonical: https://daily.dev/posts/you-had-an-issue-with-biometric-auth-passing-when-it-shouldn-t-what-went-wrong-there--emhgklmds twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: You had an issue with biometric auth passing when it shouldn’t. What went wrong there? | daily.dev og:description: A biometric authentication bug allowed unauthorized access because the fallback path wasn't properly checked. When Face ID failed, the system returned a cached... og:url: https://daily.dev/posts/you-had-an-issue-with-biometric-auth-passing-when-it-shouldn-t-what-went-wrong-there--emhgklmds og:image: https://api.daily.dev/og/posts/EMHgKLmdS.png og:image:alt: You had an issue with biometric auth passing when it shouldn’t. What went wrong there? 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. # You had an issue with biometric auth passing when it shouldn’t. What went wrong there? **[Rebeloper](https://daily.dev/sources/rebeloper)** · 1 min read · 0 upvotes · 0 comments ## Summary A biometric authentication bug allowed unauthorized access because the fallback path wasn't properly checked. When Face ID failed, the system returned a cached success result in edge cases, which went undetected for weeks. The fix required strict evaluation of authentication state on every attempt with no result reuse. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [How biometrics work on your phone: Face ID, Touch ID, and the Secure Enclave](https://daily.dev/posts/how-biometrics-work-on-your-phone-face-id-touch-id-and-the-secure-enclave-p45u4fyvu) · Medium · 0 upvotes · 0 comments - [Schneier on Security](https://daily.dev/posts/schneier-on-security-rvrzouvvo) · Schneier on Security · 0 upvotes · 0 comments - [How AI Threats Have Broken Strong Authentication](https://daily.dev/posts/how-ai-threats-have-broken-strong-authentication-fhtux8una) · Security Boulevard · 0 upvotes · 0 comments - [39 New Methods That Compromise Passkey Authentication](https://daily.dev/posts/39-new-methods-that-compromise-passkey-authentication-z1hysnxm6) · BleepingComputer · 1 upvotes · 0 comments - [I ditched passwords for passkeys, and now I'm locked into my ecosystem more than ever](https://daily.dev/posts/i-ditched-passwords-for-passkeys-and-now-i-m-locked-into-my-ecosystem-more-than-ever-vbb4ppehu) · XDA Developers · 0 upvotes · 0 comments --- [View this post on daily.dev](https://daily.dev/posts/you-had-an-issue-with-biometric-auth-passing-when-it-shouldn-t-what-went-wrong-there--emhgklmds) ```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":"You had an issue with biometric auth passing when it shouldn’t. 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