Multicore application processors are well known for their execution timing jitter, generally ascribed to interrupt activity, the behaviour of the memory hierarchy, and the dynamism of the instruction pipeline. Other sources of interference to an application program’s timing exist, however. We have grouped these under the term Über-Authority, a higher authority than the application operating system’s thread scheduler, which seizes the execution environment, prevents it from scheduling threads, and may even stop all the running threads from making progress too. This paper introduces a classification of Über-Authorities, a nomenclature for their characteristics, and offers some examples to increase awareness of the problem they create for software safety assurance and, in particular, timing guarantee.