CVE-2022-49648 – This is a memory leak vulnerability in the Linu... (How to Fix)

Q: What is the severity of CVE-2022-49648?

CVE-2022-49648 has a CVSS score of 5.5 (MEDIUM). This is a memory leak vulnerability in the Linux kernel's tracing/histograms subsystem. When specific trigger commands fail during memory allocation, kernel memory isn't properly freed, leading to gradual memory exhaustion. This affects Linux systems with kernel tracing enabled.

📋 TL;DR

This is a memory leak vulnerability in the Linux kernel's tracing/histograms subsystem. When specific trigger commands fail during memory allocation, kernel memory isn't properly freed, leading to gradual memory exhaustion. This affects Linux systems with kernel tracing enabled.

💻 Affected Systems

Products:

Linux Kernel

Versions: Specific kernel versions containing commit 46bbe5c671e06f070428b9be142cc4ee5cedebac and before the fix commits

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ✅ No

Notes: Requires kernel tracing subsystem to be enabled and accessible. Typically requires root or appropriate permissions to write to /sys/kernel/debug/tracing.

📦 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 →

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

Sustained exploitation could lead to kernel memory exhaustion, causing system instability, crashes, or denial of service through resource depletion.

🟠

Likely Case

Gradual memory leak over time when specific tracing trigger commands are used, potentially leading to performance degradation or system instability.

🟢

If Mitigated

Minimal impact if kernel tracing is disabled or the vulnerable code path isn't triggered.

🌐 Internet-Facing: LOW - Requires local access or kernel-level code execution to trigger the vulnerable code path.

🏢 Internal Only: MEDIUM - Local users or processes with appropriate permissions could trigger the vulnerability, potentially affecting system stability.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires ability to write specific trigger commands to the tracing subsystem. This typically requires elevated privileges or specific system configurations.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Fixed in kernel commits: 22eeff55679d9e7c0f768c79bfbd83e2f8142d89, 4d453eb5e1eec89971aa5b3262857ee26cfdffd3, 78a1400c42ee11197eb1f0f85ba51df9a4fdfff0, 7edc3945bdce9c39198a10d6129377a5c53559c2, eb622d5580b9e2ff694f62da6410618bd73853cb

Vendor Advisory: https://git.kernel.org/stable/c/22eeff55679d9e7c0f768c79bfbd83e2f8142d89

Restart Required: Yes

Instructions:

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

🔧 Temporary Workarounds

Disable kernel tracing

linux

Prevent access to the vulnerable tracing subsystem

echo 0 > /proc/sys/kernel/ftrace_enabled
mount -o remount,nodebug /sys/kernel/debug

Restrict debugfs access

linux

Limit access to tracing debug interface

chmod 700 /sys/kernel/debug/tracing
chown root:root /sys/kernel/debug/tracing

🧯 If You Can't Patch

Disable kernel tracing functionality completely
Implement strict access controls on /sys/kernel/debug/tracing directory

🔍 How to Verify

Check if Vulnerable:

Check kernel version and verify if it's between the vulnerable commit and fix commits. Use: uname -r and check kernel source or distribution security advisories.

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version after update matches or exceeds fixed versions. Check that the specific git commits are included in your kernel build.

📡 Detection & Monitoring

Log Indicators:

Kernel oom-killer messages
System memory exhaustion warnings
Process crashes due to memory allocation failures

Network Indicators:

None - this is a local kernel vulnerability

SIEM Query:

Search for: 'Out of memory' OR 'kernel: Out of memory' OR 'oom-killer' in system logs

📊 Metadata

CVE ID: CVE-2022-49648

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

EPSS Score: 0.04% exploit probability (10.1th percentile)

Published: February 26, 2025

Last Updated: October 1, 2025

🔗 References

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🔗 Related Vulnerabilities

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