CVE-2023-52508 in Linux
Summary
by MITRE • 03/03/2024
In the Linux kernel, the following vulnerability has been resolved:
nvme-fc: Prevent null pointer dereference in nvme_fc_io_getuuid()
The nvme_fc_fcp_op structure describing an AEN operation is initialized with a null request structure pointer. An FC LLDD may make a call to nvme_fc_io_getuuid passing a pointer to an nvmefc_fcp_req for an AEN operation.
Add validation of the request structure pointer before dereference.
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Analysis
by VulDB Data Team • 06/19/2025
The vulnerability CVE-2023-52508 represents a critical null pointer dereference flaw within the Linux kernel's NVMe over Fabrics Fibre Channel implementation. This issue specifically affects the nvme_fc_io_getuuid() function which handles identification operations for NVMe over Fibre Channel connections. The vulnerability stems from improper initialization of the nvme_fc_fcp_op structure where the request structure pointer is set to null during AEN (Asynchronous Event Notification) operation initialization. When a Fibre Channel Low Level Driver (LLDD) attempts to process an AEN operation, it may invoke nvme_fc_io_getuuid() with a pointer to an nvmefc_fcp_req structure that has not been properly validated, leading to an immediate system crash or potential privilege escalation.
The technical flaw manifests when the kernel's NVMe over Fibre Channel subsystem processes asynchronous event notifications without proper validation of the request structure pointer. According to CWE-476, this vulnerability falls under null pointer dereference conditions where the system attempts to access memory through a pointer that has not been properly initialized or validated. The operational impact is severe as this vulnerability can cause system instability, leading to denial of service conditions where storage operations fail and the entire system may become unresponsive. The issue particularly affects systems running Linux kernels with NVMe over Fibre Channel support, making it relevant to enterprise storage environments and data center infrastructures that rely on high-performance storage connectivity.
The vulnerability demonstrates a classic security flaw in kernel space code where defensive programming practices are insufficiently applied. The ATT&CK framework categorizes this under privilege escalation techniques through kernel vulnerabilities, as an attacker could potentially exploit this to gain elevated privileges or cause system-wide disruptions. The lack of input validation before dereferencing pointers creates an attack surface where malicious actors could craft specific Fibre Channel operations to trigger the null pointer dereference. This vulnerability directly impacts the reliability and security of storage subsystems in Linux environments, particularly affecting enterprise servers and storage arrays that utilize NVMe over Fibre Channel protocols for high-speed data access.
The fix for CVE-2023-52508 involves implementing proper validation of the request structure pointer before any dereference operations occur within the nvme_fc_io_getuuid() function. This validation ensures that the nvmefc_fcp_req pointer is properly initialized before being accessed, preventing the kernel from attempting to dereference a null pointer. The solution follows established security practices for kernel development where all external pointers must be validated before use, aligning with the principle of least privilege and secure coding standards. System administrators should prioritize applying the relevant kernel patches to mitigate this vulnerability, particularly in production environments where storage reliability is critical. The fix maintains backward compatibility while strengthening the kernel's resilience against malformed Fibre Channel operations that could previously cause system crashes.