CVE-2022-49842 – A use-after-free vulnerability in the Linux ker... (How to Fix)

Q: What is the severity of CVE-2022-49842?

CVE-2022-49842 has a CVSS score of 7.8 (HIGH). A use-after-free vulnerability in the Linux kernel's ASoC (ALSA System on Chip) subsystem allows local attackers to potentially crash the kernel or execute arbitrary code. This affects systems running vulnerable Linux kernel versions with ASoC functionality loaded. The vulnerability occurs during module unloading when error handling fails to properly clean up resources.

📋 TL;DR

A use-after-free vulnerability in the Linux kernel's ASoC (ALSA System on Chip) subsystem allows local attackers to potentially crash the kernel or execute arbitrary code. This affects systems running vulnerable Linux kernel versions with ASoC functionality loaded. The vulnerability occurs during module unloading when error handling fails to properly clean up resources.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific vulnerable versions not explicitly stated, but patches available for multiple stable branches

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Requires ASoC subsystem to be loaded/used. Many embedded systems and devices using ALSA audio may be affected.

📦 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 →

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, potentially leading to full system compromise.

🟠

Likely Case

Kernel panic or system crash resulting in denial of service.

🟢

If Mitigated

No impact if kernel module loading is restricted or vulnerable code paths aren't triggered.

🌐 Internet-Facing: LOW - Requires local access to exploit.

🏢 Internal Only: MEDIUM - Local attackers or malicious insiders could exploit this vulnerability.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access and ability to load/unload kernel modules. Exploitation would require bypassing kernel protections like KASLR.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Multiple stable kernel versions with commits: 2ec3f558db34, 34eee4189bce, 41fad4f712e0, 6ec27c53886c, 8d21554ec768

Vendor Advisory: https://git.kernel.org/stable/c/2ec3f558db343b045a7c7419cdbaec266b8ac1a7

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution. 2. Reboot system to load new kernel. 3. Verify kernel version matches patched release.

🔧 Temporary Workarounds

Restrict kernel module loading

linux

Prevent loading/unloading of kernel modules to block exploitation path

echo 1 > /proc/sys/kernel/modules_disabled
sysctl -w kernel.modules_disabled=1

Disable ASoC subsystem

linux

Prevent vulnerable code from being loaded if not needed

modprobe -r snd_soc_core
echo 'blacklist snd_soc_core' > /etc/modprobe.d/disable-asoc.conf

🧯 If You Can't Patch

Implement strict access controls to prevent local users from loading/unloading kernel modules
Monitor system logs for kernel panics or suspicious module operations

🔍 How to Verify

Check if Vulnerable:

Check kernel version and verify if ASoC modules are loaded: lsmod | grep snd_soc

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is updated and check dmesg for absence of use-after-free errors during module operations

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
KASAN use-after-free reports in dmesg
ASoC module loading/unloading errors

Network Indicators:

None - local exploitation only

SIEM Query:

source="kernel" AND ("KASAN" OR "use-after-free" OR "snd_soc")

📊 Metadata

CVE ID: CVE-2022-49842

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

EPSS Score: 0.02% exploit probability (5.9th percentile)

Published: May 1, 2025

Last Updated: October 1, 2025

🔗 References

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🔗 Related Vulnerabilities

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