CVE-2026-61511 - a critical vulnerability in vBulletin that allows an unauthenticated attacker to execute arbitrary code on a remote server.

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.

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 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.

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.

Open redirect vulnerability in forum/login.php in vBulletin 4.1.3 and earlier allows remote attackers to redirect users to arbitrary web sites and conduct phishing attacks via the url parameter in a lostpw action.

SQL injection vulnerability in VBulletin 3.0.10 allows remote attackers to execute arbitrary SQL commands via the featureid parameter.

SQL injection vulnerability in announcement.php in vBulletin 4.1.10 allows remote attackers to execute arbitrary SQL commands via the announcementid parameter.

SQL injection vulnerability in index.php/ajax/api/reputation/vote in vBulletin 5.0.0 Beta 11, 5.0.0 Beta 28, and earlier allows remote authenticated users to execute arbitrary SQL commands via the nodeid parameter.

Cross-site scripting (XSS) vulnerability in index.php in Jelsoft vBulletin allows remote attackers to spoof parts of a website via the loc parameter.

The Personal Sticky Threads addon 1.0.3c for vBulletin allows remote authenticated users to read the title, author, and pages of an arbitrary thread by toggling a personal sticky.

SQL injection vulnerability in VBGooglemap Hotspot Edition 1.0.3, a vBulletin module, allows remote attackers to execute arbitrary SQL commands via the mapid parameter in a showdetails action to (1) vbgooglemaphse.php and (2) mapa.php.

Cross-site scripting (XSS) vulnerability in vBulletin 3.7.2 PL1 and 3.6.10 PL3, when "Show New Private Message Notification Pop-Up" is enabled, allows remote authenticated users to inject arbitrary web script or HTML via a private message subject (aka newpm[title]).

Multiple cross-site scripting (XSS) vulnerabilities in vBulletin 3.6.10 PL2 and earlier, and 3.7.2 and earlier 3.7.x versions, allow remote attackers to inject arbitrary web script or HTML via (1) the PATHINFO (PHPSELF) or (2) the do parameter, as demonstrated by requests to upload/admincp/faq.php. NOTE: this issue can be leveraged to execute arbitrary PHP code.

Cross-site scripting (XSS) vulnerability in vBulletin 3.6.10 and 3.7.1 allows remote attackers to inject arbitrary web script or HTML via unknown vectors and an "obscure method." NOTE: the vector is probably in the redirect parameter to the Admin Control Panel (admincp/index.php).

SQL injection vulnerability in faq.php in vBulletin 3.7.0 Gold allows remote attackers to execute arbitrary SQL commands via the q parameter in a search action.

Cross-site scripting (XSS) vulnerability in forum/radioandtv.php in the Radio and TV Player addon for vBulletin allows remote registered users to inject arbitrary web script or HTML via the station parameter.

Cross-site scripting (XSS) vulnerability in vBulletin 4.1.12 allows remote attackers to inject arbitrary web script or HTML via a long string in the subject parameter when creating a post.

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.

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.

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.

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.

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.

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.

vBulletin 5.4.3 has an Open Redirect.

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 through 5.5.4 mishandles external URLs within the /core/vb/vurl.php file and the /core/vb/vurl directories.