--- title: Microsoft Patches Security Flaw That Exposed... description: Microsoft confirmed a security bug (CW1226324) in Copilot Chat that allowed the AI to bypass confidentiality labels and DLP policies, summarizing emails from... canonical: https://daily.dev/posts/microsoft-patches-security-flaw-that-exposed-confidential-emails-to-ai-o1fmgvxt4 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Microsoft Patches Security Flaw That Exposed Confidential Emails to AI | daily.dev og:description: Microsoft confirmed a security bug (CW1226324) in Copilot Chat that allowed the AI to bypass confidentiality labels and DLP policies, summarizing emails from... og:url: https://daily.dev/posts/microsoft-patches-security-flaw-that-exposed-confidential-emails-to-ai-o1fmgvxt4 og:image: https://api.daily.dev/og/posts/o1fMgVXt4.png og:image:alt: Microsoft Patches Security Flaw That Exposed Confidential Emails to AI 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. # Microsoft Patches Security Flaw That Exposed Confidential Emails to AI **[Security Boulevard](https://daily.dev/sources/securityboulevard)** · 3 min read · 0 upvotes · 0 comments ## Summary Microsoft confirmed a security bug (CW1226324) in Copilot Chat that allowed the AI to bypass confidentiality labels and DLP policies, summarizing emails from Sent Items and Drafts folders without user authorization. Active since late January, the flaw was first reported by BleepingComputer and attributed to an unspecified 'code issue.' A fix began rolling out in early February, though the number of affected Microsoft 365 business customers has not been disclosed. The incident adds to a series of Copilot security concerns, including a previously reported Reprompt vulnerability, and comes amid broader enterprise anxiety about AI tools accessing sensitive corporate data—highlighted by the European Parliament blocking built-in AI features on work devices. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Copilot Chat bug bypasses DLP on 'Confidential' email](https://daily.dev/posts/copilot-chat-bug-bypasses-dlp-on-confidential-email-gzisnirqe) · The Register · 0 upvotes · 0 comments - [Critical Copilot vulnerability allowed hackers to seal 2FA code from users](https://daily.dev/posts/critical-copilot-vulnerability-allowed-hackers-to-seal-2fa-code-from-users-ffggsogtl) · Ars Technica · 1 upvotes · 1 comments - [What to do When Your AI Guardrails Fail](https://daily.dev/posts/what-to-do-when-your-ai-guardrails-fail-hrv5vdkpx) · IT Security Guru · 0 upvotes · 0 comments - [New attack turned Microsoft 365 Copilot into 1-click data theft tool](https://daily.dev/posts/new-attack-turned-microsoft-365-copilot-into-1-click-data-theft-tool-ffqgdzkcx) · BleepingComputer · 0 upvotes · 0 comments --- Tags: [#cyber](https://daily.dev/tags/cyber), [#data-privacy](https://daily.dev/tags/data-privacy), [#ai-security](https://daily.dev/tags/ai-security), [#microsoft-copilot](https://daily.dev/tags/microsoft-copilot) [View this post on daily.dev](https://daily.dev/posts/microsoft-patches-security-flaw-that-exposed-confidential-emails-to-ai-o1fmgvxt4) ```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":"Microsoft Patches Security Flaw That Exposed Confidential Emails to AI","url":"https://daily.dev/posts/microsoft-patches-security-flaw-that-exposed-confidential-emails-to-ai-o1fmgvxt4","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/microsoft-patches-security-flaw-that-exposed-confidential-emails-to-ai-o1fmgvxt4"},"datePublished":"2026-02-18T20:28:51.074Z","dateModified":"2026-02-26T17:52:32.549Z","description":"Microsoft confirmed a security bug (CW1226324) in Copilot Chat that allowed the AI to bypass confidentiality labels and DLP policies, summarizing emails from...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/624094a36fff1d2f1ff37ec5c6a48002?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/624094a36fff1d2f1ff37ec5c6a48002?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Security Boulevard","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":"Security Boulevard","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/3613c832180040de8d85bb29f74395be","url":"https://daily.dev/sources/securityboulevard"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/microsoft-patches-security-flaw-that-exposed-confidential-emails-to-ai-o1fmgvxt4","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"cyber,data-privacy,ai-security,microsoft-copilot","timeRequired":"PT3M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Security Boulevard","item":"https://daily.dev/sources/securityboulevard"},{"@type":"ListItem","position":3,"name":"Microsoft Patches Security Flaw That Exposed Confidential Emails to AI"}]} ```