This three-volume set LNCS 16900-16902 constitutes the proceedings of the ARES 2026 International Workshops on Availability, Reliability and Security, held under the umbrella of the 21st International conference on Availability, Reliability and Security, ARES 2026, which took place in Linköping, Sweden, during August 24–27, 2026.

The 101 full papers presented in these volumes were carefully reviewed and selected from 232 submissions. They contain papers of the following workshops:

Part I: Second International Workshop on Artificial Intelligence, Cyber and Cyber-Physical Security (AI&CCPS 2026); Second International Workshop on Cybersecurity and Privacy Risk Assessments (CPRA 2026); First International Workshop on Applied Trust and Cyber Resilience (CyResTrust 2026); 5th Workshop on Cybersecurity in Industry 4.0 (SecIndustry 2026); First International Workshop on Security, Availability, and Fault-Tolerance in Edge AI Systems (SAFE-EDGE 2026); First Workshop on Sustainable Security and Awareness For nExt Generation InfRastructures (SAFER 2026); First Workshop on Security, Privacy, and Identity Management for the Digital Transformation (SPIMDT 2026).

Part II: First Workshop on Agentic AI for Cybersecurity: Offensive and Defensive Perspectives (AgentCy 2026); First Workshop on SecAviation meets SecHealth: Cybersecurity in Critical Infrastructure (AviHealthSec2026); 7th Workshop on Recent Advances in Cyber Situational Awareness and Data-Centric Approaches (CSA 2026); 7th International Workshop on Graph-based Approaches for CyberSecurity (GRASEC 2026); First International Workshop on Securing Supply Chains and Mobile Communication (IWSSCMC 2026); 19th Workshop on Digital Forensics (WSDF 2026).

Part III: First International Workshop on AI for Secure and Trustworthy Critical Infrastructure Systems (AI4TCI 2026); 10th International Workshop on Cyber Use of Information Hiding (CUING 2026); 15th International Workshop on Cyber Crime (IWCC 2026); First International Workshop on Post-Quantum
Cybersecurity Readiness and Migration (PQ-ReadySec 2026); 23rd International Workshop on Trust,
Privacy and Security in the Digital Society (TrustBus 2026).