Avo is an open source ruby on rails admin panel creation framework. The polymorphic field type stores the classes to operate on when updating a record with user input, and does not validate them in the back end. This can lead to unexpected behavior, remote code execution, or application crashes when viewing a manipulated record. This issue has been addressed in commit `ec117882d` which is expected to be included in subsequent releases. Users are advised to limit access to untrusted users until a new release is made.