External risk intelligence

Linux Kernel NVMe-FC List Corruption Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2025-40261

This vulnerability exists within the Linux kernel's NVMe over Fibre Channel (NVMe-FC) subsystem, which operates at the driver and storage protocol layer. It is not an internet-facing service or application. Access requires local, authenticated, or privileged interaction with the kernel storage stack, making exposure to the public internet impossible in normal deployments.

Halo Surface Signal: 1 out of 5 — much less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability has been identified in the Linux kernel's NVMe over Fibre Channel subsystem that could lead to system instability. The issue involves how the system manages work queues during controller deletion, potentially causing corruption and system crashes if not handled correctly. The main concern is confirming whether this specific subsystem is in use within the environment.

Prevents potential system crashes.
Important for storage infrastructure management.
Confirm relevance and exposure.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by interacting with the Linux kernel's storage management, specifically the NVMe over Fibre Channel (NVMe-FC) component. This interaction, likely occurring under specific error conditions during control deletion, could lead to a system crash. The exact method for triggering these specific error conditions is not detailed.

Requires privileged or local access.
Triggered during control deletion error handling.
Leads to a system crash.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could affect system stability and data integrity within the Linux kernel's NVMe over Fibre Channel subsystem. When specific error conditions occur during controller deletion, a race condition can lead to a kernel bug, potentially causing system crashes or data corruption. This is contingent on the presence and specific usage of the NVMe-FC feature.

System stability and data integrity.
Race condition during controller deletion.
System crashes or data corruption.

Operational Fix

Recommended remediation, mitigation, and detection steps

The Linux kernel's NVMe over Fibre Channel subsystem is affected by this vulnerability, indicating that infrastructure or platform teams responsible for storage and kernel management are likely accountable. The first practical step involves identifying all systems running the affected kernel, confirming the presence and reachability of the NVMe-FC interface, and then prioritizing remediation based on the criticality of these systems to business operations.

Kernel and infrastructure teams own the issue.
Verify NVMe-FC interface exposure and reachability.
Plan coordinated kernel updates during maintenance.

Supplementary metadata

CVSS vector

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Frequently asked questions

What is the Linux kernel NVMe-FC component?

The NVMe over Fibre Channel (NVMe-FC) component is a driver-level feature in the Linux kernel. It allows servers to communicate with high-speed storage area networks (SANs) using the NVMe protocol over a Fibre Channel fabric. It is used in enterprise environments to connect compute resources to large-scale, high-performance storage infrastructure.

What happens during this CVE-2025-40261 vulnerability?

This vulnerability is a memory-related issue involving how the kernel manages background tasks, specifically when deleting a storage controller. If a task is still running after it should have been stopped, it can cause memory corruption. This instability triggers a kernel bug that results in a system crash, as the kernel cannot safely proceed when its internal data structures are corrupted.

How is this vulnerability triggered?

The flaw is triggered by specific, internal error conditions that occur during the deletion of an NVMe-FC storage controller. It does not occur during normal, error-free operation. An attacker cannot trigger this simply by sending network traffic; it requires complex, precise timing and existing access to influence the kernel's storage management processes during a controller teardown.

Is my system exposed to this vulnerability?

According to Halo Surface Signal, this vulnerability is very unlikely to be reachable from the internet. Because the issue resides deep within the kernel's storage driver stack, it is not an internet-facing service. Exposure requires local, privileged, or authenticated access to the kernel's storage management functions, which is not possible through standard public-facing network interfaces.

What should I do to address CVE-2025-40261?

Your first step is to identify which of your systems are actively using the NVMe-FC feature. Once identified, focus on standard infrastructure maintenance: track kernel update releases from your distribution vendor and plan to deploy the fix during your regular maintenance cycles. There is no need for emergency network-level mitigation since the vulnerability is not exposed to the internet.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.