Description
vBulletin versions 5.5.4 through 5.6.2 allows remote command execution via a crafted subWidgets POST data to /ajax/render/widget_tabbedcontainer_tab_panel. This vulnerability is a bypass of the fix for the previous vulnerability, CVE-2019-16759, which allows attackers to send a crafted HTTP request with a specified template name and malicious PHP code, and leads to remote code execution.
Remediation
Upgrade to the latest version of vBulletin.
References
Exploiting vBulletin: "A Tale of a Patch Fail"
Exploits in the Wild for vBulletin Pre-Auth RCE Vulnerability CVE-2020-17496