vBulletin versions 5.5.4 through 5.6.2 allow 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.
View the template here CVE-2020-17496.yaml
References:
https://cwe.mitre.org/data/definitions/78.html