  Metaverse is expected to emerge as a new paradigm for the next-generation
Internet, providing fully immersive and personalised experiences to socialize,
work, and play in self-sustaining and hyper-spatio-temporal virtual world(s).
The advancements in different technologies like augmented reality, virtual
reality, extended reality (XR), artificial intelligence (AI), and 5G/6G
communication will be the key enablers behind the realization of AI-XR
metaverse applications. While AI itself has many potential applications in the
aforementioned technologies (e.g., avatar generation, network optimization,
etc.), ensuring the security of AI in critical applications like AI-XR
metaverse applications is profoundly crucial to avoid undesirable actions that
could undermine users' privacy and safety, consequently putting their lives in
danger. To this end, we attempt to analyze the security, privacy, and
trustworthiness aspects associated with the use of various AI techniques in
AI-XR metaverse applications. Specifically, we discuss numerous such challenges
and present a taxonomy of potential solutions that could be leveraged to
develop secure, private, robust, and trustworthy AI-XR applications. To
highlight the real implications of AI-associated adversarial threats, we
designed a metaverse-specific case study and analyzed it through the
adversarial lens. Finally, we elaborate upon various open issues that require
further research interest from the community.
