Dispatch's notification service uses Jinja templates to generate messages to users. Jinja permits code execution within blocks, which were neither properly sanitized nor sandboxed. This vulnerability enables users to construct command line scripts in their custom message templates, which are then executed whenever these notifications are rendered and sent out.
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.