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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-17496
• https://blog.exploitee.rs/2020/exploiting-vbulletin-a-tale-of-patch-fail/
• https://forum.vbulletin.com/forum/vbulletin-announcements/vbulletin-announcements_aa/4445227-vbulletin-5-6-0-5-6-1-5-6-2-security-patch
• https://seclists.org/fulldisclosure/2020/Aug/5
• https://cwe.mitre.org/data/definitions/78.html