CVE-2025-48769 is a Use After Free (CWE-416) vulnerability identified in the Apache NuttX Real-Time Operating System (RTOS), specifically within the virtual filesystem (VFS) rename functionality implemented in fs/vfs/fs_rename. The root cause stems from a recursive implementation that improperly manages memory buffers: two different pointer variables reuse a single buffer, allowing a user-controlled size buffer reallocation to write to a previously freed heap chunk. This memory mismanagement can lead to unintended side effects such as incorrect virtual filesystem rename or move operations, potentially corrupting filesystem state or causing undefined behavior. The vulnerability affects all NuttX versions starting from 7.20 up to but not including 12.11.0, where the issue has been fixed. The threat is particularly relevant for systems that expose virtual filesystem services with write permissions over the network, for example, FTP servers running on NuttX-based devices. Although no public exploits have been reported, the vulnerability could be leveraged by an attacker with network access to cause memory corruption, leading to denial of service or potentially arbitrary code execution depending on the device context. The absence of a CVSS score necessitates an assessment based on the impact on confidentiality, integrity, and availability, ease of exploitation, and scope of affected systems. Given that NuttX is widely used in embedded and IoT devices, the vulnerability poses a significant risk to devices relying on network-exposed filesystem operations. The recommended mitigation is to upgrade to Apache NuttX version 12.11.0, which addresses the memory management flaw.

For European organizations, the impact of CVE-2025-48769 can be substantial, especially those deploying embedded systems, industrial control systems, or IoT devices running Apache NuttX RTOS with network-exposed virtual filesystem services. Successful exploitation could lead to memory corruption, causing device instability, denial of service, or unintended filesystem operations that may disrupt critical processes. This can affect sectors such as manufacturing, automotive, telecommunications, and smart infrastructure, where NuttX is commonly embedded. The integrity of filesystem operations is critical in these environments, and corruption could lead to data loss or operational failures. Additionally, if exploited in devices controlling safety-critical functions, it could pose safety risks. The network-exposed nature of some vulnerable services increases the attack surface, making remote exploitation feasible without user interaction or authentication. This elevates the risk profile for European organizations relying on such devices, potentially impacting operational continuity and security compliance.

European organizations should immediately inventory all devices and systems running Apache NuttX RTOS, particularly those versions from 7.20 up to before 12.11.0. Prioritize upgrading these systems to version 12.11.0, which contains the patch for this vulnerability. For devices where immediate upgrade is not feasible, implement network segmentation and restrict access to virtual filesystem services, especially FTP or similar protocols, to trusted networks only. Employ strict firewall rules to limit exposure of vulnerable services to the internet or untrusted networks. Monitor network traffic for unusual rename or filesystem operation patterns that could indicate exploitation attempts. Additionally, implement runtime protections such as memory corruption detection tools or intrusion detection systems tailored for embedded environments. Engage with device vendors to ensure timely firmware updates and validate that patches are applied correctly. Finally, incorporate this vulnerability into vulnerability management and incident response plans to ensure rapid detection and remediation.