CVE-2025-38264 in Linux
Summary
by MITRE • 07/09/2025
In the Linux kernel, the following vulnerability has been resolved:
nvme-tcp: sanitize request list handling
Validate the request in nvme_tcp_handle_r2t() to ensure it's not part of any list, otherwise a malicious R2T PDU might inject a loop in request list processing.
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Analysis
by VulDB Data Team • 05/03/2026
The vulnerability identified as CVE-2025-38264 resides within the Linux kernel's NVMe over TCP implementation, specifically in the nvme_tcp_handle_r2t() function. This flaw represents a critical security issue that could enable malicious actors to manipulate the request list processing mechanism through carefully crafted R2T Protocol Data Units. The vulnerability stems from inadequate validation of request objects before they are processed, creating a potential pathway for attackers to inject malformed requests that could cause the system to enter an infinite loop during request list handling operations. The NVMe TCP protocol implementation is responsible for managing network communications between NVMe storage devices and hosts, making this vulnerability particularly concerning for storage infrastructure security. The issue affects systems that utilize NVMe over TCP for storage communications, potentially impacting enterprise storage arrays, data centers, and any environment where NVMe over TCP is deployed as a storage transport mechanism.
The technical flaw manifests when the nvme_tcp_handle_r2t() function processes R2T PDUs without properly validating whether the request object being handled is already part of another list structure. This validation gap allows attackers to craft malicious R2T PDUs that reference request objects already present in active list structures, potentially causing the kernel's request list processing logic to enter an infinite loop. The vulnerability operates by exploiting the absence of proper list membership checks before request processing, which could lead to a denial of service condition where the kernel becomes unresponsive due to continuous loop iterations. This type of vulnerability falls under the CWE-457 category of "Use of Uninitialized Variable" and more specifically aligns with CWE-835 which addresses "Loop with Unreachable Exit Condition (Loop Iterator Not Updated)" in the context of improper list handling operations. The flaw represents a classic case of insufficient input validation and inadequate state management within kernel space code.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it could potentially allow for more sophisticated attacks depending on the system configuration and attack surface. When exploited, the infinite loop condition could cause the target system to become unresponsive, effectively rendering storage services unavailable to legitimate users. This type of vulnerability is particularly dangerous in enterprise environments where storage availability is critical for business operations, as it could lead to significant downtime and potential data access disruptions. The vulnerability affects systems running Linux kernels that implement NVMe over TCP functionality, making it relevant to a wide range of storage infrastructure deployments including cloud storage systems, enterprise storage arrays, and server environments utilizing NVMe over TCP for high-performance storage communications. The attack vector requires network access to the target system and the ability to send specially crafted R2T PDUs, making it accessible to attackers with network-level privileges.
Mitigation strategies for CVE-2025-38264 should prioritize immediate kernel updates from vendors that contain the specific fix for the nvme_tcp_handle_r2t() function. The recommended approach involves applying security patches that implement proper list membership validation before request processing, ensuring that request objects are not already part of active list structures before being added to or processed within the request handling logic. Organizations should also implement network segmentation and access controls to limit exposure to the NVMe over TCP ports and services, reducing the attack surface available to potential adversaries. Monitoring systems should be configured to detect unusual patterns in request processing that might indicate exploitation attempts, particularly focusing on network traffic patterns associated with R2T PDUs. The fix addresses the vulnerability at its root cause by implementing proper validation checks that prevent malformed requests from being processed in ways that could lead to list processing loops, aligning with the ATT&CK technique T1499.004 for "Endpoint Denial of Service" and representing a fundamental security improvement in kernel space memory management and list handling operations.