CVE-2022-48856 – This CVE describes a memory leak vulnerability ... (How to Fix)

Q: What is the severity of CVE-2022-48856?

CVE-2022-48856 has a CVSS score of 5.5 (MEDIUM). This CVE describes a memory leak vulnerability in the Linux kernel's gianfar ethernet driver. When the gfar_get_ts_info function is called via ethtool, it fails to properly release a reference count on a device tree node, potentially leading to kernel memory exhaustion. This affects systems using the gianfar network driver on PowerPC or ARM platforms.

📋 TL;DR

This CVE describes a memory leak vulnerability in the Linux kernel's gianfar ethernet driver. When the gfar_get_ts_info function is called via ethtool, it fails to properly release a reference count on a device tree node, potentially leading to kernel memory exhaustion. This affects systems using the gianfar network driver on PowerPC or ARM platforms.

💻 Affected Systems

Products:

Linux kernel with gianfar ethernet driver

Versions: Linux kernel versions before the fix commits (specific versions vary by distribution)

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems using the gianfar network driver, typically found on PowerPC and ARM platforms like Freescale/NXP QorIQ processors.

📦 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...

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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

An attacker could repeatedly trigger the vulnerable function to cause kernel memory exhaustion, leading to system instability, denial of service, or potential kernel panic.

🟠

Likely Case

Memory leak gradually consumes kernel resources over time, potentially causing system performance degradation or instability after extended operation.

🟢

If Mitigated

With proper kernel memory management and monitoring, the impact is limited to potential performance issues rather than complete system failure.

🌐 Internet-Facing: LOW - Requires local access or ability to execute code on the system to trigger the vulnerable function.

🏢 Internal Only: MEDIUM - Local users or processes could exploit this to degrade system performance or cause denial of service.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: NO

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires local access and ability to call the vulnerable ethtool function. No public exploits have been reported.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Fixed in Linux kernel stable releases via commits referenced in CVE

Vendor Advisory: https://git.kernel.org/stable/c/0e1b9a2078e07fb1e6e91bf8badfd89ecab1e848

Restart Required: Yes

Instructions:

1. Update Linux kernel to version containing the fix. 2. Check distribution-specific security advisories. 3. Reboot system to load new kernel.

🔧 Temporary Workarounds

Disable gianfar driver if not needed

linux

Remove or blacklist the gianfar kernel module if the affected hardware is not in use

echo 'blacklist gianfar' >> /etc/modprobe.d/blacklist.conf
rmmod gianfar

🧯 If You Can't Patch

Monitor kernel memory usage for unusual growth patterns
Restrict local user access to systems using gianfar driver

🔍 How to Verify

Check if Vulnerable:

Check if gianfar driver is loaded: lsmod | grep gianfar. Check kernel version against distribution security advisories.

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes fix commits or is newer than vulnerable versions. Check with: uname -r

📡 Detection & Monitoring

Log Indicators:

Kernel oom-killer messages
System instability logs
Memory exhaustion warnings in dmesg

Network Indicators:

None - local vulnerability only

SIEM Query:

Search for kernel panic logs, memory exhaustion alerts, or repeated ethtool command execution

📊 Metadata

CVE ID: CVE-2022-48856

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

CWE: CWE-401

Published: July 16, 2024

Last Updated: November 21, 2024

🔗 References

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🔗 Related Vulnerabilities

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