--- title: CVE-2026-29000 | daily.dev description: A maximum severity vulnerability (CVE-2026-29000) was disclosed in pac4j-jwt's JwtAuthenticator component. The flaw allows a remote unauthenticated attacker... canonical: https://daily.dev/posts/cve-2026-29000-ac6dexegl twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: CVE-2026-29000 | daily.dev og:description: A maximum severity vulnerability (CVE-2026-29000) was disclosed in pac4j-jwt's JwtAuthenticator component. The flaw allows a remote unauthenticated attacker... og:url: https://daily.dev/posts/cve-2026-29000-ac6dexegl og:image: https://api.daily.dev/og/posts/Ac6dexeGL.png og:image:alt: CVE-2026-29000 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-2026-29000 **[Arctic Wolf](https://daily.dev/sources/arcticwolf)** · 2 min read · 0 upvotes · 0 comments ## Summary A maximum severity vulnerability (CVE-2026-29000) was disclosed in pac4j-jwt's JwtAuthenticator component. The flaw allows a remote unauthenticated attacker who knows the server's RSA public key to bypass authentication and impersonate any user, including admins, by submitting a crafted JWE containing an unsigned PlainJWT (alg=none). The bug stems from a logic error where a null SignedJWT causes signature verification to be skipped entirely, allowing unverified claims to build a user profile. Affected versions are pac4j-jwt prior to 4.5.9, 5.7.9, and 6.3.3. No active exploitation has been observed yet, but a public proof-of-concept exists. Upgrading to the fixed releases is strongly recommended. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [CVE-2026-82329: Unauthenticated Administrative Access in…](https://daily.dev/posts/cve-2026-82329-unauthenticated-administrative-access-in--jp5ers0bt) · Sliver C2 Documentation · 0 upvotes · 0 comments - [HTB: Principal](https://daily.dev/posts/htb-principal-zkodzkeg6) · 0xdf hacks stuff · 0 upvotes · 0 comments - [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 - [Artifactory Vulnerabilities Under Active Exploitation Enable Authentication Bypass and Admin Access](https://daily.dev/posts/artifactory-vulnerabilities-under-active-exploitation-enable-authentication-bypass-and-admin-access-39gsdirjz) · InfoQ · 0 upvotes · 0 comments - [JWT-backed authentication can be replayed across organizations](https://daily.dev/posts/jwt-backed-authentication-can-be-replayed-across-organizations-xbeidguk2) · RUBYLAND · 0 upvotes · 0 comments --- Tags: [#authentication](https://daily.dev/tags/authentication), [#cryptography](https://daily.dev/tags/cryptography), [#jwt](https://daily.dev/tags/jwt) [View this post on daily.dev](https://daily.dev/posts/cve-2026-29000-ac6dexegl) ```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-2026-29000","url":"https://daily.dev/posts/cve-2026-29000-ac6dexegl","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/cve-2026-29000-ac6dexegl"},"datePublished":"2026-03-06T19:56:36.812Z","dateModified":"2026-03-06T19:57:29.942Z","description":"A maximum severity vulnerability (CVE-2026-29000) was disclosed in pac4j-jwt's JwtAuthenticator component. 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