This paper presents a knowledge systematization of safety and security threats to computer-assisted agents (CUAs). While CUAs, evolving into LLM-based systems, can autonomously manipulate desktop applications, web pages, and mobile apps, they pose new safety and security risks due to the vulnerabilities of LLM inference and the complexity of integrating diverse software components and multimodal inputs. Through a literature review, this paper presents a definition suitable for safety analysis of CUAs, a classification of current safety threats, a comprehensive classification of defense strategies, and benchmarks, datasets, and evaluation metrics used to evaluate the safety and performance of CUAs. This provides guidance for future research and the design and deployment of secure CUAs.