--- title: CVE-2026-55040: Microsoft SharePoint JWT Token... description: Rapid7 Labs discovered two chained vulnerabilities in Microsoft SharePoint through a zero-day research project, including CVE-2026-55040, a JWT token... canonical: https://daily.dev/posts/cve-2026-55040-microsoft-sharepoint-jwt-token-authentication-bypass-fixed--qwfb7arbc twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: CVE-2026-55040: Microsoft SharePoint JWT Token Authentication Bypass (FIXED) | daily.dev og:description: Rapid7 Labs discovered two chained vulnerabilities in Microsoft SharePoint through a zero-day research project, including CVE-2026-55040, a JWT token... og:url: https://daily.dev/posts/cve-2026-55040-microsoft-sharepoint-jwt-token-authentication-bypass-fixed--qwfb7arbc og:image: https://api.daily.dev/og/posts/QWFB7ARbC.png og:image:alt: CVE-2026-55040: Microsoft SharePoint JWT Token Authentication Bypass (FIXED) 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. # CVE-2026-55040: Microsoft SharePoint JWT Token Authentication Bypass (FIXED) **[Rapid7 Cybersecurity Blog](https://daily.dev/sources/rapid7-blog)** · 6 min read · 0 upvotes · 0 comments ## Summary Rapid7 Labs discovered two chained vulnerabilities in Microsoft SharePoint through a zero-day research project, including CVE-2026-55040, a JWT token authentication bypass (CVSS 5.3 Medium) that allows unauthenticated attackers to impersonate any SharePoint user. When chained with a separate RCE vulnerability (to be patched in August 2026), the exploit achieves unauthenticated remote code execution. The research notably used AI agents over 24 active days, 96 sessions, and ~80,000 tool calls, with the second sprint in March yielding the successful exploit chain. The authentication bypass was patched in July 2026; full technical details will be published within 30 days of disclosure. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Microsoft SharePoint JWT Token Authentication Bypass Technical Analysis \(CVE-2026-55040\)](https://daily.dev/posts/microsoft-sharepoint-jwt-token-authentication-bypass-technical-analysis-cve-2026-55040--pz2fge3so) · Rapid7 Cybersecurity Blog · 0 upvotes · 0 comments - [Hackers leverage new Microsoft SharePoint exploit in attacks](https://daily.dev/posts/hackers-leverage-new-microsoft-sharepoint-exploit-in-attacks-poikstdjk) · BleepingComputer · 0 upvotes · 0 comments --- Tags: [#security](https://daily.dev/tags/security), [#jwt](https://daily.dev/tags/jwt) [View this post on daily.dev](https://daily.dev/posts/cve-2026-55040-microsoft-sharepoint-jwt-token-authentication-bypass-fixed--qwfb7arbc) ```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":"CVE-2026-55040: Microsoft SharePoint JWT Token Authentication Bypass (FIXED)","url":"https://daily.dev/posts/cve-2026-55040-microsoft-sharepoint-jwt-token-authentication-bypass-fixed--qwfb7arbc","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/cve-2026-55040-microsoft-sharepoint-jwt-token-authentication-bypass-fixed--qwfb7arbc"},"datePublished":"2026-07-14T13:18:46.068Z","dateModified":"2026-07-14T13:19:13.293Z","description":"Rapid7 Labs discovered two chained vulnerabilities in Microsoft SharePoint through a zero-day research project, including CVE-2026-55040, a JWT token...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/403310fc83643451d0e643aaed18bd42?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/403310fc83643451d0e643aaed18bd42?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Rapid7 Cybersecurity Blog","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":"Rapid7 Cybersecurity Blog","logo":"https://media.daily.dev/image/upload/logos/placeholder.jpg","url":"https://daily.dev/sources/rapid7-blog"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/cve-2026-55040-microsoft-sharepoint-jwt-token-authentication-bypass-fixed--qwfb7arbc","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"security,jwt","timeRequired":"PT6M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Rapid7 Cybersecurity Blog","item":"https://daily.dev/sources/rapid7-blog"},{"@type":"ListItem","position":3,"name":"CVE-2026-55040: Microsoft SharePoint JWT Token Authentication Bypass (FIXED)"}]} ```