External risk intelligence

Linux Kernel skb Corruption Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2023-54094

This vulnerability exists in the Linux kernel network stack during skb fragmentation processing. While it is network-reachable and processes traffic, it is a low-level kernel component rather than a directly exposed web application or service. Its reachability depends on the specific network traffic being processed, making it possible but not inherently designed for public internet exposure.

Halo Surface Signal: 3 out of 5 — possibly public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability in the Linux kernel's network component could lead to system instability or crashes when processing certain network traffic. This issue affects how the kernel handles packet segmentation, and if exploited, could disrupt network operations. The main concern at this time is confirming if our specific network configurations are exposed.

A kernel flaw can crash systems processing network data.
It impacts core networking functionality.
Confirm relevance and exposure to our systems.

Attack Path

How an attacker could exploit the issue

An attacker could reach this vulnerability by sending specially crafted network traffic to a system running the affected Linux kernel. This traffic would be processed by the kernel's networking stack, specifically during the segmentation of packet fragments. If the crafted traffic triggers a particular condition within the fragmentation logic, it can lead to corruption of network buffers, potentially causing a system crash.

Network access is required.
Triggered by processing fragmented network packets.
Can lead to system instability and crashes.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could impact the stability and integrity of the Linux kernel's network processing. When handling specific network packet segmentation, the kernel may encounter a NULL pointer dereference, leading to a crash. This condition could arise when processing certain types of network traffic that trigger the bug, potentially affecting systems engaged in network communication.

Kernel network data integrity.
Corrupted packets during segmentation.
System instability or crashes.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability within the Linux kernel's network stack necessitates immediate attention from infrastructure and platform teams. The first critical action is to identify all systems running the affected kernel, confirm their network exposure and business criticality, and then assign ownership for remediation planning.

Infrastructure and platform teams own resolution.
Verify kernel version and network exposure.
Plan and schedule system upgrades or patches.

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 in the context of CVE-2023-54094?

The Linux kernel is the foundational core of the operating system that manages hardware resources and essential services. In this case, the vulnerability exists within its network stack, specifically concerning the processing of data packets using Generic Receive Offload (GRO) lists. This component is responsible for efficiently handling high volumes of incoming network traffic, making it a critical piece of infrastructure for any system performing network communication.

What is the nature of the CVE-2023-54094 vulnerability?

This vulnerability is a memory-related flaw involving the corruption of socket buffers (skb) during packet segmentation. When the kernel attempts to break down certain network packets, an error in the logic can lead to a NULL pointer dereference. In plain terms, the kernel tries to access memory that does not exist or is not available during specific packet processing tasks, which causes the system to crash or become unstable.

How is this vulnerability triggered by network traffic?

An attacker triggers this bug by sending specially crafted network packets to a target system. The vulnerability manifests specifically during the segmentation of packet fragments within the kernel's networking stack. It is not triggered by standard, well-formed traffic; the condition requires specific network data that forces the kernel into a flawed path during its fragmentation logic, leading to the reported memory error.

Do I need to worry if my systems are internal-only?

While Halo Surface Signal classifies this as having external reachability potential due to the network-based attack vector, your specific risk depends on whether the system processes untrusted or fragmented traffic. Because the flaw lies deep within the kernel's network stack rather than in a user-facing application, the vulnerability is not limited to internet-facing services alone; any system receiving complex network traffic may potentially be at risk.

When should I begin responding to CVE-2023-54094?

You should begin your response by identifying which systems in your environment are running the affected Linux kernel versions. Once identified, prioritize these systems based on their business criticality and network exposure. After scoping the affected assets, coordinate with your infrastructure or platform teams to plan for system updates or kernel patches to mitigate the potential for instability and crashes.

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.