The proliferation of personally owned smartphones, tablets and laptops within institutional workspaces has reshaped the perimeter of organisational information assets, dissolving the historical distinction between sanctioned enterprise endpoints and consumer-grade devices. In Nigerian federal universities, administrative offices increasingly tolerate or implicitly encourage staff to perform sensitive tasks, including student record processing, financial reconciliation, examination workflows and human-resources transactions, on devices that are not centrally provisioned. This study interrogates the convergence of consumer device adoption and the cybersecurity exposure of administrative units within the federal university subsystem, examining how device heterogeneity, weak enforcement of mobile-device-management protocols, intermittent power, ageing campus network architectures and limited security awareness culminate in a markedly elevated risk profile. Drawing on protection-motivation theory, the deterrence framework and the unified theory of acceptance and use of technology, the review synthesises evidence from peer-reviewed literature, regulatory documentation and Africa-focused empirical work to argue that the consumerisation of computing within Nigerian public higher education has outpaced the institutional capacity to govern it. The analysis identifies five interlocking risk domains: device-layer vulnerabilities, network-layer exposure, application-layer leakage, governance-policy fragmentation and user-behaviour deficits. It further contends that the absence of binding ICT-security frameworks tailored to the operational realities of federal universities has created a permissive environment for credential theft, unauthorised data exfiltration and ransomware contamination of institutional records. The paper closes by advancing a layered, context-sensitive risk-mitigation architecture that integrates technical controls, policy reform, awareness pedagogy and institutional governance, and outlines an agenda for empirical inquiry capable of generating actionable evidence for university administrators, regulators and policymakers operating within Nigeria’s federal higher education subsystem.