The product does not properly "clean up" and remove temporary or supporting resources after they have been used.
Temporary files and other supporting resources should be deleted/released immediately after they are no longer needed.
It is possible to overflow the number of temporary files because directories typically have limits on the number of files allowed. This could create a denial of service problem.
Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
Effectiveness: High