In the rapidly evolving landscape of mobile networks, the importance of fortifying security, ensuring privacy, and enhancing resilience cannot be overstated. As we transition towards more sophisticated network architectures of future B5G/6G systems, the complexity and heterogeneity of these systems introduce unprecedented challenges in wireless cybersecurity. The integration of cloud-native software techniques, reliance on virtualized infrastructure, and the shift towards open-source components magnify the attack surface, making mobile networks increasingly susceptible to sophisticated cyber-attacks. These developments necessitate a paradigm shift in how we approach security in mobile networks. The workshop aims to address these critical issues by fostering discussions on innovative security measures, privacy-preserving technologies, and strategies to bolster network resilience against emerging threats. It is imperative to acknowledge that security is not a one-size-fits-all solution; rather, it requires a balanced consideration of risk, cost, and usability to tailor defenses that protect against both current and future threats while ensuring the network’s mission objectives are met. Furthermore, the advent of technologies like AI and the expansion in the numbers and diversity of end-user devices introduce both opportunities and vulnerabilities. AI, while a powerful tool for network optimization and automation, also presents a novel attack vector that can be exploited by adversaries. The workshop seeks to illuminate these issues, promoting a holistic understanding of the security landscape in mobile networks. It aims to gather experts from academia, industry, and regulatory bodies to collaboratively explore the residual risks inherited from current ICT infrastructures and the increased risks posed by the advent of B5G/6G networks. Discussions will not only cover the technical aspects of securing advanced networks but also delve into the economic and operational challenges of implementing high-security standards. By examining real-world breaches and theoretical attack scenarios, participants will gain insights into the evolving cyber-attack ecosystem and the continuous arms race between the network and its adversaries. This workshop is a clarion call to the community to prioritize security, privacy, and resilience in the design and operation of mobile networks, ensuring they remain trustworthy backbones of our digital society. This workshop was first organized in 2024 at the IEEE CNS 2024 in Taipei.