CVE-2025-39841 – This CVE describes a use-after-free vulnerabili... (How to Fix)

Q: What is the severity of CVE-2025-39841?

CVE-2025-39841 has a CVSS score of 7.8 (HIGH). This CVE describes a use-after-free vulnerability in the Linux kernel's lpfc SCSI driver. An attacker could exploit this to cause a kernel panic (denial of service) or potentially execute arbitrary code with kernel privileges. Systems using the lpfc driver for Fibre Channel storage are affected.

📋 TL;DR

This CVE describes a use-after-free vulnerability in the Linux kernel's lpfc SCSI driver. An attacker could exploit this to cause a kernel panic (denial of service) or potentially execute arbitrary code with kernel privileges. Systems using the lpfc driver for Fibre Channel storage are affected.

💻 Affected Systems

Products:

Linux kernel with lpfc driver

Versions: Linux kernel versions containing the vulnerable lpfc driver code (specific versions not provided in CVE description)

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems using the lpfc driver for Fibre Channel storage. Systems without this driver loaded are not vulnerable.

📦 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 →

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 →

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

Kernel memory corruption leading to arbitrary code execution with kernel privileges, potentially resulting in full system compromise.

🟠

Likely Case

Kernel panic causing system crash and denial of service, requiring a reboot to restore functionality.

🟢

If Mitigated

No impact if the vulnerable driver is not loaded or if the system is patched.

🌐 Internet-Facing: LOW - This vulnerability requires local access or specialized storage network access.

🏢 Internal Only: MEDIUM - Internal attackers with local access or access to the storage network could exploit this.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires local access or access to the storage network. The vulnerability is in a specific driver code path that may require specific conditions to trigger.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Patched in kernel commits: 367cb5ffd8a8a4c85dc89f55e7fa7cc191425b11, 55658c7501467ca9ef3bd4453dd920010db8bc13, 897f64b01c1249ac730329b83f4f40bab71e86c7, 95b63d15fce5c54a73bbf195e1aacb5a75b128e2, 9dba9a45c348e8460da97c450cddf70b2056deb3

Vendor Advisory: https://git.kernel.org/stable/c/367cb5ffd8a8a4c85dc89f55e7fa7cc191425b11

Restart Required: Yes

Instructions:

1. Update to a Linux kernel version containing the fix commits. 2. Reboot the system to load the patched kernel. 3. Verify the kernel version after reboot.

🔧 Temporary Workarounds

Unload lpfc driver

linux

Remove the vulnerable driver if Fibre Channel storage is not required

modprobe -r lpfc

Blacklist lpfc driver

linux

Prevent the driver from loading at boot

echo 'blacklist lpfc' >> /etc/modprobe.d/blacklist.conf

🧯 If You Can't Patch

Restrict local access to systems using lpfc driver
Isolate storage network from untrusted systems

🔍 How to Verify

Check if Vulnerable:

Check if lpfc driver is loaded: lsmod | grep lpfc

Check Version:

uname -r

Verify Fix Applied:

Check kernel version contains fix commits: uname -r and verify with distribution patch notes

📡 Detection & Monitoring

Log Indicators:

Kernel oops messages
System crashes/panics
lpfc driver error messages in dmesg

Network Indicators:

Unusual storage network traffic patterns

SIEM Query:

source="kernel" AND ("lpfc" OR "use-after-free" OR "kernel panic")

📊 Metadata

CVE ID: CVE-2025-39841

CVSS v3 Score: 7.8 (HIGH)

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

CWE: CWE-787

EPSS Score: 0.02% exploit probability (5.3th percentile)

Published: September 19, 2025

Last Updated: January 20, 2026

🔗 References

https://git.kernel.org/stable/c/367cb5ffd8a8a4c85dc89f55e7fa7cc191425b11 Patch
https://git.kernel.org/stable/c/55658c7501467ca9ef3bd4453dd920010db8bc13 Patch
https://git.kernel.org/stable/c/897f64b01c1249ac730329b83f4f40bab71e86c7 Patch
https://git.kernel.org/stable/c/95b63d15fce5c54a73bbf195e1aacb5a75b128e2 Patch
https://git.kernel.org/stable/c/9dba9a45c348e8460da97c450cddf70b2056deb3 Patch
https://git.kernel.org/stable/c/ab34084f42ee06a9028d67c78feafb911d33d111 Patch
https://git.kernel.org/stable/c/baa39f6ad79d372a6ce0aa639fbb2f1578479f57 Patch
https://git.kernel.org/stable/c/d96cc9a1b57725930c60b607423759d563b4d900 Patch
https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html Third Party Advisory,Mailing List
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html Third Party Advisory,Mailing List

📤 Share & Export

📄 Export Markdown 📋 Export JSON

🔗 Related Vulnerabilities

If you're affected by CVE-2025-39841, you might also want to check these: