An issue was discovered in MCMS 5.2.7. There is a CSRF vulnerability that can add an administrator account via ms/basic/manager/save.do.
https://github.com/advisories/GHSA-gp39-qj5f-43qv
https://gist.github.com/aaaahuia/f708c6c8a320e0f3afbb9247903c4670