List storage requires memory. Executed programs (or evaluated expressions) may ruin very quickly the memory management strategies of the application when operating lists.
Applications using the list library would limit memory allocation or risk memory exhaustion.
Programs operating large and / or many lists referring one another may experience performance degradation related to automatic object management. List operations commanding tests on whether list objects need dismantling (freeing, collecting, that is) are likely to be slow if the tested objects are part of large such sets of objects referring one another.
See Referable Objects.
See Detecting Cycles.
With memory allocation limited the list library does not present significant security challenges.