vBulletin 3.8.7 is vulnerable to a denial-of-service condition via the misc.php?do=buddylist endpoint. If an authenticated user has a sufficiently large buddy list, processing the list can consume excessive memory, exhausting system resources and crashing the forum.
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 "var_dump"("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 verify_serialized 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/widget_tabbedcontainer_tab_panel 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.
vBulletin 5.5.4 through 5.6.2 allows remote command execution via crafted subWidgets data in an ajax/render/widget_tabbedcontainer_tab_panel request. NOTE: this issue exists because of an incomplete fix for CVE-2019-16759.