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.
Exploitability
AV:NAC:LPR:NUI:NScope
S:CImpact
C:HI:HA:H10/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HOther