The procdeutf function in includes/functionsvbseocpabstract.php in vBSEO 3.5.0, 3.5.1, 3.5.2, 3.6.0, and earlier allows remote attackers to insert and execute arbitrary PHP code via "complex curly syntax" in the charrepl parameter, which is inserted into a regular expression that is processed by the pregreplace function with the eval switch.
vBSeo before 3.6.0PL2 allows XSS via the member.php u parameter.