External risk intelligence

Linux Kernel mlx5e XSK Invalid Buffer Access

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2023-54223

This vulnerability is located deep within the Linux kernel networking stack driver (mlx5e) regarding memory management for AF_XDP sockets. It is a driver-level implementation defect requiring specific kernel configurations and local context to trigger, not a network-reachable service or internet-facing application endpoint.

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 vulnerability in the Linux kernel relates to how network data buffers are handled. Specifically, it addresses an issue where a buffer could be released twice when using a particular network feature, potentially leading to system instability or crashes. The fix ensures buffers are managed correctly to prevent this double release.

Incorrect buffer release in Linux kernel.
Could cause system crashes or instability.
Confirm relevance and assess exposure.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by triggering specific network traffic handling within the Linux kernel's mlx5e driver. This driver is responsible for managing network data packets and their associated memory buffers. When using XDP_REDIRECT with AF_XDP sockets in receive mode on legacy request queues, a flaw in how buffer release flags are managed can lead to the same buffer being released twice.

Requires specific kernel configuration.
Triggered by network packet redirection.
Can lead to system instability or crash.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could affect system stability and data integrity when using XDP sockets in receive mode on specific hardware. The issue stems from an incorrect buffer release mechanism in the Linux kernel's mlx5e driver, potentially leading to a crash.

Kernel system stability.
Invalid buffer access could occur.
System crashes may result.

Operational Fix

Recommended remediation, mitigation, and detection steps

The Linux kernel's network driver is responsible for this vulnerability. Infrastructure or platform teams managing kernel components and network acceleration should investigate. The first practical step is to identify systems using the affected network driver with XDP enabled, confirm exposure, and then plan remediation based on operational risk.

Infrastructure/Platform teams own the issue.
Verify XDP and AF_XDP socket usage.
Coordinate kernel updates in maintenance windows.

Supplementary metadata

CVSS vector

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Frequently asked questions

What is the mlx5e driver in the Linux kernel?

The mlx5e driver is a component within the Linux kernel designed to support Mellanox Technologies' network adapters. It handles high-speed data transmission and reception, specifically managing how the operating system interacts with the network card's hardware queues. This driver includes specialized features for packet processing, such as support for XDP (eXpress Data Path), which allows for high-performance networking by processing packets directly at the interface level.

What is the vulnerability in CVE-2023-54223?

CVE-2023-54223 involves a memory management error within the mlx5e driver. Technically, this is an invalid memory access issue. When the driver processes network packets using specific high-performance socket configurations, it incorrectly attempts to release the same memory buffer twice. This logic flaw can cause the system to encounter a fatal exception, leading to a kernel crash or system instability.

How is this buffer release issue triggered?

The issue is triggered when using AF_XDP sockets in receive mode on legacy request queues while employing the XDP_REDIRECT function. It requires this specific combination of kernel features and configurations to occur. If a system is not using XDP_REDIRECT or is not configured to utilize legacy request queues with these high-performance sockets, the problematic code path that leads to the double-release of the buffer is not invoked.

Is my system at risk according to Halo Surface Signal?

Halo Surface Signal indicates that this vulnerability is very unlikely to be exploited remotely. The flaw exists deep within the kernel's networking stack and requires specific local configurations rather than being a flaw in an internet-facing network service. While categorized by CVSS as network-based, the actual implementation defect is constrained to specialized, low-level driver operations rather than exposed application endpoints.

What are the first steps to address this vulnerability?

If you manage infrastructure running the Linux kernel, begin by identifying which systems are utilizing the mlx5e driver and have XDP or AF_XDP socket features enabled. Once identified, evaluate the operational necessity of these configurations. Consult your kernel distribution's security bulletins to determine if a patched kernel version is available for your specific environment and schedule updates during standard maintenance cycles.

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.