External risk intelligence

Linux Kernel macb Memory Corruption Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2023-54257

This vulnerability exists in a low-level Linux kernel networking driver (macb) related to DMA memory management. It is a driver-level issue, not a network-accessible service or application-layer flaw. Exploitation would require local execution context, not remote interaction over the network, despite the network-related nature of the driver.

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

This issue involves a memory corruption flaw in a Linux kernel component that handles networking. The problem, which can lead to persistent network and storage failures, has been addressed in recent updates. The primary concern is confirming whether this specific component is in use and exposed within the organization's environment.

The issue involves Linux kernel network component errors.
Understanding its presence is key for leadership.
Confirm relevance and exposure to understand potential impact.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by triggering a memory corruption issue within the Linux kernel's networking component, specifically the macb driver, when it's using extended buffer descriptor mode. This could lead to network and MMC failures on affected devices.

Entry condition: Local execution context.
Trigger point: DMA memory operations in macb driver.
Resulting risk: System instability and data corruption.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability in the Linux kernel's networking component could lead to system instability when handling network traffic. It involves a memory corruption issue within the extended buffer descriptor mode of the macb driver. When this occurs, it can manifest as a permanent failure of networking and MMC functions on affected devices.

Kernel networking memory.
Improper DMA memory management.
Unstable system and network functions.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability impacts the Linux kernel's networking subsystem, specifically the macb driver's handling of DMA memory. Ownership likely falls to the Linux kernel development team or the embedded systems/platform team responsible for managing the kernel build and deployment. The first practical step is to confirm the presence of the affected kernel component and assess its exposure within the environment, identifying the accountable owner for remediation and planning based on the criticality of affected systems.

Kernel developers own the fix.
Verify affected kernel components.
Plan system updates.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

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Frequently asked questions

What is the macb component in the Linux kernel?

The macb component is a network device driver within the Linux kernel designed to support Ethernet controllers, commonly found in embedded systems. It manages how the hardware communicates with system memory to transmit and receive data packets, acting as the critical bridge between the device's physical network connection and the operating system's networking stack.

What kind of vulnerability is CVE-2023-54257?

This is a memory corruption vulnerability. It occurs when the macb driver improperly manages Direct Memory Access (DMA) operations while using extended buffer descriptor mode. Essentially, the driver attempts to release memory that it does not own or has already mismanaged, leading to internal errors that can crash the networking subsystem.

How is this memory corruption triggered?

The issue is triggered by specific internal DMA memory operations within the macb driver. It is not caused by sending crafted network packets from the outside. The system must already be running with the affected driver configuration, and the memory corruption occurs as a result of the kernel's own internal handling of data transfers, rather than external input.

Do I need to worry about this if my device is on the internet?

While the vulnerability involves a network driver, Halo Surface Signal analysis indicates it is very unlikely to be exploited remotely. The flaw is local to the kernel's memory management logic. Even if a device is internet-facing, an attacker would need local execution context on the device to influence the specific memory conditions required to trigger this failure.

How should I respond to this Linux kernel vulnerability?

Your first step is to audit your systems to identify those running the macb driver in extended buffer descriptor mode. Once identified, consult your platform or kernel engineering teams. They will need to verify if your specific kernel build includes the relevant fixes for this driver and schedule a routine update to the patched kernel version provided by your distribution or vendor.

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.