CVE-2022-49836 – This CVE describes a memory leak vulnerability ... (How to Fix)

Q: What is the severity of CVE-2022-49836?

CVE-2022-49836 has a CVSS score of 5.5 (MEDIUM). This CVE describes a memory leak vulnerability in the Linux kernel's siox subsystem. When device registration fails in siox_device_add(), the kernel fails to properly clean up allocated memory, leading to resource exhaustion over time. This affects systems using the siox (Simple I/O) subsystem, typically industrial control or embedded Linux systems.

📋 TL;DR

This CVE describes a memory leak vulnerability in the Linux kernel's siox subsystem. When device registration fails in siox_device_add(), the kernel fails to properly clean up allocated memory, leading to resource exhaustion over time. This affects systems using the siox (Simple I/O) subsystem, typically industrial control or embedded Linux systems.

💻 Affected Systems

Products:

Linux kernel

Versions: Kernel versions with siox subsystem support (specific affected versions in stable trees: see references)

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ✅ No

Notes: Only vulnerable if siox subsystem is loaded/used. Not all systems use this industrial I/O subsystem.

📦 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 →

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, denial of service, or potential kernel panic/crash.

🟠

Likely Case

Gradual memory leak leading to performance degradation and eventual system instability requiring reboot.

🟢

If Mitigated

Minimal impact with proper monitoring and regular system maintenance.

🌐 Internet-Facing: LOW - Requires local access or kernel module loading capability.

🏢 Internal Only: MEDIUM - Could be exploited by malicious local users or through other vulnerabilities to degrade system stability.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires ability to trigger siox device registration failures repeatedly. Likely requires local access or kernel module loading privileges.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Patched in stable kernel trees (see references for specific commits)

Vendor Advisory: https://git.kernel.org/stable/c/0a5da069603ecc3d7aa09167450235462adaa295

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution vendor. 2. Reboot system to load new kernel. 3. Verify siox subsystem is not leaking memory.

🔧 Temporary Workarounds

Disable siox subsystem

linux

Prevent loading of siox kernel module if not required

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

🧯 If You Can't Patch

Monitor kernel memory usage for unusual increases
Restrict local user access and kernel module loading capabilities

🔍 How to Verify

Check if Vulnerable:

Check kernel version and if siox module is loaded: 'uname -r' and 'lsmod | grep siox'

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is patched and monitor /proc/meminfo for stable kernel memory usage

📡 Detection & Monitoring

Log Indicators:

Kernel oops messages
Out of memory errors in dmesg
Increasing kernel memory usage in system logs

Network Indicators:

None - local vulnerability

SIEM Query:

source="kernel" AND ("out of memory" OR "kernel panic" OR "siox")

📊 Metadata

CVE ID: CVE-2022-49836

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: 0.02% exploit probability (5.7th percentile)

Published: May 1, 2025

Last Updated: November 10, 2025

🔗 References

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