CVE-2025-38331 – A vulnerability in the Linux kernel's Cortina e... (How to Fix)

Q: What is the severity of CVE-2025-38331?

CVE-2025-38331 has a CVSS score of 5.5 (MEDIUM). A vulnerability in the Linux kernel's Cortina ethernet driver causes system instability when TCP offload engine (TOE) and TCP segmentation offload (TSO) features are not both enabled. This can lead to system lockups and crashes under network load. Systems using affected Linux kernel versions with Cortina ethernet hardware are vulnerable.

📋 TL;DR

A vulnerability in the Linux kernel's Cortina ethernet driver causes system instability when TCP offload engine (TOE) and TCP segmentation offload (TSO) features are not both enabled. This can lead to system lockups and crashes under network load. Systems using affected Linux kernel versions with Cortina ethernet hardware are vulnerable.

💻 Affected Systems

Products:

Linux kernel with Cortina ethernet driver

Versions: Specific kernel versions containing the vulnerable code (check git commits for exact ranges)

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems with Cortina ethernet hardware. The vulnerability manifests as instability rather than traditional security compromise.

📦 What is this software?

Debian Linux by Debian

View all CVEs affecting Debian Linux →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

⚠️ Risk & Real-World Impact

🔴

Worst Case

System becomes completely unresponsive, requiring hard reboot and potentially causing data loss or service disruption.

🟠

Likely Case

System instability under network load, with lockups or crashes occurring after minutes to hours of operation.

🟢

If Mitigated

No impact if patched or if system doesn't use Cortina ethernet hardware.

🌐 Internet-Facing: MEDIUM - Systems exposed to network traffic could experience instability from legitimate traffic.

🏢 Internal Only: MEDIUM - Internal network traffic could still trigger the instability.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: NO

Unauthenticated Exploit: ✅ No

Complexity: LOW - No exploitation needed, vulnerability triggers from normal network traffic.

This is a stability bug rather than a traditional security vulnerability. It causes denial of service through system instability.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions containing the fix commits: 1b503b790109d19710ec83c589c3ee59e95347ec, 2bd434bb0eeb680c2b3dd6c68ca319b30cb8d47f, 6a07e3af4973402fa199a80036c10060b922c92c, a37888a435b0737128d2d9c6f67b8d608f83df7a, ebe12e232f1d58ebb4b53b6d9149962b707bed91

Vendor Advisory: https://git.kernel.org/stable/c/

Restart Required: Yes

Instructions:

1. Update Linux kernel to version containing the fix commits. 2. Reboot system to load new kernel. 3. Verify driver stability under network load.

🔧 Temporary Workarounds

Disable Cortina ethernet interface

linux

Temporarily disable the affected network interface to prevent instability.

sudo ip link set <interface_name> down

Reduce network load

linux

Limit network traffic to the affected system to delay or prevent lockups.

sudo tc qdisc add dev <interface_name> root tbf rate 100mbit burst 32kbit latency 400ms

🧯 If You Can't Patch

Replace Cortina ethernet hardware with alternative network interface
Implement network traffic shaping to reduce load on affected interface

🔍 How to Verify

Check if Vulnerable:

Check if system has Cortina ethernet hardware: lspci | grep -i cortina; Check kernel version: uname -r

Check Version:

uname -r

Verify Fix Applied:

Test system stability under network load using iperf3 or similar tools for extended periods.

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
System lockup reports in syslog
Network interface errors

Network Indicators:

Sudden loss of network connectivity
Increased packet loss on affected interface

SIEM Query:

source="kernel" AND ("panic" OR "lockup" OR "cortina")

📊 Metadata

CVE ID: CVE-2025-38331

CVSS v3 Score: 5.5 (MEDIUM)

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Score: 0.02% exploit probability (4.3th percentile)

Published: July 10, 2025

Last Updated: December 19, 2025

🔗 References

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