CVE-2024-49852 – This CVE describes a use-after-free vulnerabili... (How to Fix)

Q: What is the severity of CVE-2024-49852?

CVE-2024-49852 has a CVSS score of 7.8 (HIGH). This CVE describes a use-after-free vulnerability in the Linux kernel's SCSI driver (libefc) that could allow local attackers to crash the system or potentially execute arbitrary code. The vulnerability occurs when the kernel incorrectly accesses memory after it has been freed during nport deletion operations. Systems running affected Linux kernel versions with the libefc SCSI driver loaded are vulnerable.

📋 TL;DR

This CVE describes a use-after-free vulnerability in the Linux kernel's SCSI driver (libefc) that could allow local attackers to crash the system or potentially execute arbitrary code. The vulnerability occurs when the kernel incorrectly accesses memory after it has been freed during nport deletion operations. Systems running affected Linux kernel versions with the libefc SCSI driver loaded are vulnerable.

💻 Affected Systems

Products:

Linux kernel with libefc SCSI 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: ✅ No

Notes: Only vulnerable if the libefc driver (for Emulex Fibre Channel adapters) is loaded and in use. Most systems won't have this driver loaded by default.

📦 What is this software?

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

Local privilege escalation to kernel-level code execution, leading to complete system compromise and potential lateral movement.

🟠

Likely Case

Kernel panic or system crash causing denial of service, requiring system reboot.

🟢

If Mitigated

Limited to denial of service if exploit fails to achieve code execution, with system stability restored after reboot.

🌐 Internet-Facing: LOW - This is a local vulnerability requiring access to the system.

🏢 Internal Only: MEDIUM - Internal users with shell access could exploit this to crash systems or potentially gain elevated privileges.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires local access and knowledge of kernel memory layout. No public exploits are known at this time.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions with the fix commits: 16a570f07d870a285b0c0b0d1ca4dff79e8aa5ff, 2e4b02fad094976763af08fec2c620f4f8edd9ae, 7c2908985e4ae0ea1b526b3916de9e5351650908, 98752fcd076a8cbc978016eae7125b4971be1eec, abc71e89170ed32ecf0a5a29f31aa711e143e941

Vendor Advisory: https://git.kernel.org/stable/c/16a570f07d870a285b0c0b0d1ca4dff79e8aa5ff

Restart Required: Yes

Instructions:

1. Update to a kernel version containing the fix commits. 2. Reboot the system. 3. Verify the fix is applied by checking kernel version or examining the driver code.

🔧 Temporary Workarounds

Unload libefc driver

linux

Remove the vulnerable driver module if not required for system operation

sudo rmmod libefc
sudo modprobe -r libefc

Blacklist driver

linux

Prevent the driver from loading at boot

echo 'blacklist libefc' | sudo tee /etc/modprobe.d/blacklist-libefc.conf

🧯 If You Can't Patch

Restrict local user access to systems with vulnerable driver loaded
Implement strict privilege separation and limit users who can load/unload kernel modules

🔍 How to Verify

Check if Vulnerable:

Check if libefc driver is loaded: lsmod | grep libefc. If loaded, check kernel version against affected ranges.

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes fix commits or that libefc driver is not loaded.

📡 Detection & Monitoring

Log Indicators:

Kernel oops messages
System crash/panic logs
Unexpected driver reload messages

Network Indicators:

None - this is a local vulnerability

SIEM Query:

Search for kernel panic events or unexpected system reboots on hosts with libefc driver

📊 Metadata

CVE ID: CVE-2024-49852

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-416

Published: October 21, 2024

Last Updated: November 3, 2025

🔗 References

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🔗 Related Vulnerabilities

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