CVE-2022-48796 – This CVE describes a use-after-free vulnerabili... (How to Fix)

Q: What is the severity of CVE-2022-48796?

CVE-2022-48796 has a CVSS score of 7.8 (HIGH). This CVE describes a use-after-free vulnerability in the Linux kernel's IOMMU subsystem. When a device probe fails and frees memory, a parallel deferred probe worker can access the freed memory, potentially leading to kernel crashes or privilege escalation. This affects Linux systems with IOMMU support enabled.

📋 TL;DR

This CVE describes a use-after-free vulnerability in the Linux kernel's IOMMU subsystem. When a device probe fails and frees memory, a parallel deferred probe worker can access the freed memory, potentially leading to kernel crashes or privilege escalation. This affects Linux systems with IOMMU support enabled.

💻 Affected Systems

Products:

Linux kernel

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

Operating Systems: Linux distributions with vulnerable kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Requires IOMMU subsystem to be enabled and used. Most modern Linux distributions with IOMMU support are 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel panic leading to system crash, or potential privilege escalation to kernel mode allowing full system compromise.

🟠

Likely Case

System instability, kernel crashes, or denial of service due to memory corruption.

🟢

If Mitigated

System remains stable with proper patching; unpatched systems may experience occasional crashes during device probing.

🌐 Internet-Facing: LOW - This vulnerability requires local access to trigger and is not directly exploitable over network.

🏢 Internal Only: MEDIUM - Local attackers or malicious processes could potentially exploit this to crash the system or escalate privileges.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: HIGH

Exploitation requires precise timing and local access. The race condition makes reliable exploitation challenging.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Fixed in kernel commits: 65ab30f6a6952fa9ee13009862736cf8d110e6e5, b54240ad494300ff0994c4539a531727874381f4, cb86e511e78e796de6947b8f3acca1b7c76fb2ff, f74fc4b5bd533ea3d30ce47cccb8ef8d21fda85a

Vendor Advisory: https://git.kernel.org/stable/c/65ab30f6a6952fa9ee13009862736cf8d110e6e5

Restart Required: Yes

Instructions:

1. Update Linux kernel to version containing the fix commits. 2. Check your distribution's security advisories for specific patched versions. 3. Reboot the system after kernel update.

🔧 Temporary Workarounds

Disable IOMMU support

linux

Disable IOMMU subsystem to prevent the vulnerable code path from being executed

Add 'iommu=off' to kernel boot parameters in GRUB configuration

🧯 If You Can't Patch

Implement strict access controls to limit local user privileges
Monitor system logs for kernel crashes or memory corruption warnings

🔍 How to Verify

Check if Vulnerable:

Check kernel version and compare with distribution's security advisory. Vulnerable if using kernel before fix commits.

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes the fix commits or check with 'uname -r' and compare against patched versions from your distribution.

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
KASAN reports of use-after-free
System crashes during device initialization

Network Indicators:

None - this is a local vulnerability

SIEM Query:

Search for kernel panic logs or KASAN error reports in system logs

📊 Metadata

CVE ID: CVE-2022-48796

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: July 16, 2024

Last Updated: January 10, 2025

🔗 References

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🔗 Related Vulnerabilities

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