CVE-2025-22097 – This CVE describes a use-after-free and double-... (How to Fix)

Q: What is the severity of CVE-2025-22097?

CVE-2025-22097 has a CVSS score of 7.8 (HIGH). This CVE describes a use-after-free and double-free vulnerability in the Linux kernel's vkms (Virtual Kernel Mode Setting) driver. If driver initialization fails, the cleanup function may access or free memory that's already been freed, potentially leading to kernel crashes or privilege escalation. This affects Linux systems using the vkms driver, typically in virtualized or testing environments.

📋 TL;DR

This CVE describes a use-after-free and double-free vulnerability in the Linux kernel's vkms (Virtual Kernel Mode Setting) driver. If driver initialization fails, the cleanup function may access or free memory that's already been freed, potentially leading to kernel crashes or privilege escalation. This affects Linux systems using the vkms driver, typically in virtualized or testing environments.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific affected kernel versions not specified in CVE, but patches exist in stable branches

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems using the vkms driver, which is typically enabled for virtualization, testing, or headless systems requiring virtual displays.

📦 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 →

⚠️ 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 when vkms driver initialization fails.

🟢

If Mitigated

Limited impact if vkms driver isn't used or initialization succeeds normally.

🌐 Internet-Facing: LOW - vkms driver is typically used internally for virtual displays and not exposed externally.

🏢 Internal Only: MEDIUM - Systems using vkms driver for virtualization or testing could experience crashes or privilege escalation.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires triggering vkms driver initialization failure, which may require specific conditions or local access.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Patches available in Linux kernel stable branches (commits referenced in CVE)

Vendor Advisory: https://git.kernel.org/stable/c/1f68f1cf09d06061eb549726ff8339e064eddebd

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from distribution vendor. 2. Rebuild kernel if compiling from source with patches. 3. Reboot system to load new kernel.

🔧 Temporary Workarounds

Disable vkms driver

linux

Prevent loading of vulnerable vkms driver module

echo 'blacklist vkms' >> /etc/modprobe.d/blacklist-vkms.conf
rmmod vkms

Build kernel without vkms

linux

Compile kernel without vkms driver support

In kernel config: CONFIG_DRM_VKMS=n

🧯 If You Can't Patch

Disable vkms driver module loading via kernel command line or blacklisting
Avoid using virtualization features that require vkms driver

🔍 How to Verify

Check if Vulnerable:

Check if vkms module is loaded: lsmod | grep vkms. If loaded and kernel version is unpatched, system is vulnerable.

Check Version:

uname -r

Verify Fix Applied:

Check kernel version against patched versions from distribution vendor, and verify vkms module loads without errors.

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
Oops messages related to vkms driver
System crashes during boot or driver initialization

Network Indicators:

None - this is a local kernel vulnerability

SIEM Query:

source="kernel" AND ("vkms" OR "use-after-free" OR "double free")

📊 Metadata

CVE ID: CVE-2025-22097

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: 0.07% exploit probability (22th percentile)

Published: April 16, 2025

Last Updated: November 3, 2025

🔗 References

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