Opencast before 8.1 and 7.6 allows almost arbitrary identifiers for media packages and elements to be used. This can be problematic for operation and security since such identifiers are sometimes used for file system operations which may lead to an attacker being able to escape working directories and write files to other locations. In addition, Opencast's Id.toString(…) vs Id.compact(…) behavior, the latter trying to mitigate some of the file system problems, can cause errors due to identifier mismatch since an identifier may unintentionally change. This issue is fixed in Opencast 7.6 and 8.1.
The product receives input from an upstream component, but it does not restrict or incorrectly restricts the input before it is used as an identifier for a resource that may be outside the intended sphere of control.
The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.