CVE-2026-61511 - a critical vulnerability in vBulletin that allows an unauthenticated attacker to execute arbitrary code on a remote server.
Certain vBulletin versions might allow attackers to execute arbitrary PHP code by abusing Template Conditionals in the template engine. By crafting template code in an alternative PHP function invocation syntax, such as the "vardump"("test") syntax, attackers can bypass security checks and execute arbitrary PHP code, as exploited in the wild in May 2025.
vBulletin 5.0.0 through 5.7.5 and 6.0.0 through 6.0.3 allows unauthenticated users to invoke protected API controllers' methods when running on PHP 8.1 or later, as demonstrated by the /api.php?method=protectedMethod pattern, as exploited in the wild in May 2025.
A cross-site scripting (XSS) vulnerability in the Admin Control Panel of vBulletin 5.7.5 and 6.0.0 allows attackers to execute arbitrary web scripts or HTML via the /login.php?do=login url parameter.
vBulletin before 5.6.9 PL1 allows an unauthenticated remote attacker to execute arbitrary code via a crafted HTTP request that triggers deserialization. This occurs because verifyserialized checks that a value is serialized by calling unserialize and then checking for errors. The fixed versions are 5.6.7 PL1, 5.6.8 PL1, and 5.6.9 PL1.
vBulletin 5.5.4 through 5.6.2 allows remote command execution via crafted subWidgets data in an ajax/render/widgettabbedcontainertabpanel request. NOTE: this issue exists because of an incomplete fix for CVE-2019-16759. ALSO NOTE: CVE-2020-7373 is a duplicate of CVE-2020-17496. CVE-2020-17496 is the preferred CVE ID to track this vulnerability.
The Admin CP in vBulletin 5.6.3 allows XSS via an Occupation Title or Description to User Profile Field Manager.
The Admin CP in vBulletin 5.6.3 allows XSS via an Announcement Title to Channel Manager.
The Admin CP in vBulletin 5.6.3 allows XSS via a Junior Member Title to User Title Manager.
The Admin CP in vBulletin 5.6.3 allows XSS via a Style Options Settings Title to Styles Manager.
The Admin CP in vBulletin 5.6.3 allows XSS via a Title of a Child Help Item in the Login/Logoff part of the User Manual.
The Admin CP in vBulletin 5.6.3 allows XSS via the admincp/search.php?do=dosearch URI.
The Admin CP in vBulletin 5.6.3 allows XSS via the Paid Subscription Email Notification field in the Options.
The Admin CP in vBulletin 5.6.3 allows XSS via a Rank Type to User Rank Manager.
The Admin CP in vBulletin 5.6.3 allows XSS via a Smilie Title to Smilies Manager.
The Admin CP in vBulletin 5.6.3 allows XSS via an admincp/attachment.php&do=rebuild&type= URI.
vBulletin before 5.5.6pl1, 5.6.0 before 5.6.0pl1, and 5.6.1 before 5.6.1pl1 has incorrect access control.
vBulletin 5.5.4 allows SQL Injection via the ajax/api/hook/getHookList or ajax/api/widget/getWidgetList where parameter.
vBulletin through 5.5.4 mishandles custom avatars.
vBulletin before 5.5.4 allows clickjacking.
vBulletin through 5.5.4 mishandles external URLs within the /core/vb/vurl.php file and the /core/vb/vurl directories.
vBulletin 5.4.3 has an Open Redirect.
vBulletin 5.x through 5.1.6 allows remote authenticated users to bypass authorization checks and inject private messages into conversations via vectors related to an input validation failure.
The media-file upload feature in vBulletin before 3.8.7 Patch Level 6, 3.8.8 before Patch Level 2, 3.8.9 before Patch Level 1, 4.x before 4.2.2 Patch Level 6, 4.2.3 before Patch Level 2, 5.x before 5.2.0 Patch Level 3, 5.2.1 before Patch Level 1, and 5.2.2 before Patch Level 1 allows remote attackers to conduct SSRF attacks via a crafted URL that results in a Redirection HTTP status code.
SQL injection vulnerability in forumrunner/includes/moderation.php in vBulletin before 4.2.2 Patch Level 5 and 4.2.3 before Patch Level 1 allows remote attackers to execute arbitrary SQL commands via the postids parameter to forumrunner/request.php, as exploited in the wild in July 2016.
The vBApiHook::decodeArguments method in vBulletin 5 Connect 5.1.2 through 5.1.9 allows remote attackers to conduct PHP object injection attacks and execute arbitrary PHP code via a crafted serialized object in the arguments parameter to ajax/api/hook/decodeArguments.
Open redirect vulnerability in go.php in vBulletin 4.2.1 allows remote attackers to redirect users to arbitrary web sites and conduct phishing attacks via a URL in the url parameter.
Cross-site scripting (XSS) vulnerability in admincp/apilog.php in vBulletin 4.2.2 and earlier, and 5.0.x through 5.0.5 allows remote authenticated users to inject arbitrary web script or HTML via a crafted XMLRPC API request, as demonstrated using the client name.
SQL injection vulnerability in includes/api/4/breadcrumbscreate.php in vBulletin 4.2.2, 4.2.1, 4.2.0 PL2, and earlier allows remote authenticated users to execute arbitrary SQL commands via the conceptid argument in an xmlrpc API request.
SQL injection vulnerability in vBulletin 5.0.4 through 5.1.3 Alpha 5 allows remote attackers to execute arbitrary SQL commands via the criteria[startswith] parameter to ajax/render/memberlistitems.