The following look like good candidates.
- CWE-915: Improperly Controlled Modification of Dynamically-Determined Object Attributes <https://cwe.mitre.org/data/definitions/915.html> (Ruby on Rails Mass assignment bug)
- CWE-502: Deserialization of Untrusted Data <https://cwe.mitre.org/data/definitions/502.html>
- CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection') <https://cwe.mitre.org/data/definitions/470.html>
I think the one assigned (CWE-20:) is not a good approach to dealing with the "class" of weaknesses.
- CWE-20: Improper Input Validation <https://cwe.mitre.org/data/definitions/20.html>
As long as you see this as a "CWE-20: Improper Input Validation" class problem, it seems like you try to fix this with a deny-list approach or a partial allow-list approach that needs additional fixing some time in the future.