External risk intelligence

Linux Kernel NTFS Runlist Reallocation Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-74570

This vulnerability is located within the Linux kernel NTFS filesystem driver. Filesystem drivers are internal kernel components that process data from local storage media; they are not network services and do not provide an internet-facing surface, making public exposure via the network highly unlikely.

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 resolved in the Linux kernel's NTFS file system driver. This issue relates to how memory is allocated when processing file system data, and while it has been fixed, its potential impact requires confirmation of relevance and exposure for your specific environment.

Memory allocation issue in file system driver.
Confirm relevance and exposure for your systems.
Understand potential internal system impact.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by crafting a malicious NTFS filesystem structure. When the Linux kernel attempts to process this structure, a flaw in how it calculates memory allocation sizes for runlists could be triggered. This could lead to a critical system compromise.

Entry condition: Malicious NTFS filesystem.
Trigger point: Processing filesystem runlists.
Resulting risk: Complete system compromise.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability in the Linux kernel's NTFS filesystem driver could potentially allow for a denial-of-service attack when processing malformed NTFS runlist data. When supported by the advisory, this could affect system stability.

Kernel data integrity.
Malformed NTFS data input.
System instability or crash.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability resides within the Linux kernel's NTFS filesystem driver. Ownership likely falls to the team managing the Linux infrastructure or platform, which in turn may need to coordinate with the vendor if the kernel is not directly managed. The immediate first step is to identify all systems running the affected kernel version, assess exposure, and determine business criticality to prioritize remediation.

Infrastructure or platform teams own remediation.
Verify affected systems and business criticality.
Plan and coordinate kernel updates.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is the Linux kernel NTFS driver and why does it matter?

The Linux kernel NTFS driver is a core component that allows your operating system to read and write files stored on NTFS-formatted drives, which are the standard file system for Windows. It functions at the heart of the system to manage data access from local storage media, ensuring that the kernel correctly interprets the structure of files and folders on those drives.

What is the vulnerability in CVE-2026-74570?

This vulnerability involves an integer overflow weakness. When the kernel needs to change the size of a 'runlist'—a structure used to track where files are located on a disk—it may perform an unsafe calculation. If the calculation overflows, the system might allocate an incorrect amount of memory, potentially leading to system instability or security compromises when handling maliciously formatted NTFS data.

How can this vulnerability be triggered?

An attacker needs to provide a maliciously crafted NTFS filesystem structure that the kernel is then forced to process. Simply having the driver installed does not trigger the bug; the system must actively attempt to mount or read from a disk image or device containing the specifically malformed runlist data. Routine operations on benign, standard NTFS drives will not trigger this issue.

Is my system at risk according to Halo Surface Signal?

Halo Surface Signal indicates that exploitation is very unlikely because this driver manages local storage, not network traffic. Since the NTFS driver is an internal kernel component and not an internet-facing service, it does not provide an easy entry point for remote attackers. Risk is primarily focused on scenarios where an untrusted local storage device is connected to the system.

How should I respond to this Linux kernel update?

First, identify which of your servers or workstations are running kernel versions that include the NTFS driver. Once identified, prioritize these systems based on how often they interact with untrusted or externally sourced NTFS storage media. Work with your infrastructure or platform team to plan and deploy the official kernel update that includes the hardened memory allocation logic.

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.