Unrestricted file upload vulnerability in ImperialBB 2.3.5 and earlier allows remote authenticated users to upload and execute arbitrary PHP code by placing a .php filename in the Upload_Avatar parameter and sending the image/gif content type.
Improper Control of Generation of Code The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.