--- title: vBulletin fixes critical pre-auth RCE flaw with public... description: A critical pre-authentication remote code execution vulnerability (CVE-2026-61511) has been discovered in vBulletin forum software affecting versions up to... canonical: https://daily.dev/posts/vbulletin-fixes-critical-pre-auth-rce-flaw-with-public-exploit-eqvnukac0 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: vBulletin fixes critical pre-auth RCE flaw with public exploit | daily.dev og:description: A critical pre-authentication remote code execution vulnerability (CVE-2026-61511) has been discovered in vBulletin forum software affecting versions up to... og:url: https://daily.dev/posts/vbulletin-fixes-critical-pre-auth-rce-flaw-with-public-exploit-eqvnukac0 og:image: https://api.daily.dev/og/posts/EQVnUKAc0.png og:image:alt: vBulletin fixes critical pre-auth RCE flaw with public exploit 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. # vBulletin fixes critical pre-auth RCE flaw with public exploit **[BleepingComputer](https://daily.dev/sources/bleepingcomputer)** · 3 min read · 0 upvotes · 0 comments ## Summary A critical pre-authentication remote code execution vulnerability (CVE-2026-61511) has been discovered in vBulletin forum software affecting versions up to 5.7.5 and 6.2.1. The flaw resides in the 'runMaths()' function, which fails to sanitize user input before passing it to PHP's eval() function. Attackers can exploit it via a crafted request to the 'ajax/render/[template]' endpoint, bypassing restrictions using the 'phpfuck' technique. A public proof-of-concept exploit has been released, significantly lowering the attack barrier. vBulletin 6.2.2 patches the issue, with backported patches for 6.2.1, 6.2.0, and 6.1.6. Users on the 5.x branch are advised to upgrade as no patch will be issued for that branch. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [phpBB forum fixes auth bypass bug lurking for a decade](https://daily.dev/posts/phpbb-forum-fixes-auth-bypass-bug-lurking-for-a-decade-khey5ws8c) · BleepingComputer · 0 upvotes · 1 comments - [Critical phpBB Vulnerability: Auth Bypass \+ RCE Since 2014](https://daily.dev/posts/critical-phpbb-vulnerability-auth-bypass-rce-since-2014-636hneaei) · Aikido Security · 0 upvotes · 0 comments - [CVE-2026-48907: How the Joomla JCE Exploit Works and What to Do About It](https://daily.dev/posts/cve-2026-48907-how-the-joomla-jce-exploit-works-and-what-to-do-about-it-nnouuvxo2) · Latest Hacking News · 0 upvotes · 0 comments --- Tags: [#security](https://daily.dev/tags/security), [#php](https://daily.dev/tags/php) [View this post on daily.dev](https://daily.dev/posts/vbulletin-fixes-critical-pre-auth-rce-flaw-with-public-exploit-eqvnukac0) ```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":"vBulletin fixes critical pre-auth RCE flaw with public exploit","url":"https://daily.dev/posts/vbulletin-fixes-critical-pre-auth-rce-flaw-with-public-exploit-eqvnukac0","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/vbulletin-fixes-critical-pre-auth-rce-flaw-with-public-exploit-eqvnukac0"},"datePublished":"2026-07-28T18:12:50.235Z","dateModified":"2026-07-28T18:48:42.357Z","description":"A critical pre-authentication remote code execution vulnerability (CVE-2026-61511) has been discovered in vBulletin forum software affecting versions up to...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/26ea8364d0d25959a729507ac02b18d2?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/26ea8364d0d25959a729507ac02b18d2?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"BleepingComputer","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":"BleepingComputer","logo":"https://media.daily.dev/image/upload/s--as8nJ3qy--/f_auto,q_auto/v1774959951/logos/bleepingcomputer?_a=BAMAMiWQ0","url":"https://daily.dev/sources/bleepingcomputer"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/vbulletin-fixes-critical-pre-auth-rce-flaw-with-public-exploit-eqvnukac0","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"security,php","timeRequired":"PT3M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"BleepingComputer","item":"https://daily.dev/sources/bleepingcomputer"},{"@type":"ListItem","position":3,"name":"vBulletin fixes critical pre-auth RCE flaw with public exploit"}]} ```