CVE-2024-39499 – A vulnerability in the Linux kernel's VMCI driv... (How to Fix)

Q: What is the severity of CVE-2024-39499?

CVE-2024-39499 has a CVSS score of 7.1 (HIGH). A vulnerability in the Linux kernel's VMCI driver allows local attackers to potentially leak sensitive information through speculative execution. The issue occurs when user-controlled event data is used as an array index without proper sanitization, potentially exposing kernel memory contents. This affects systems running vulnerable Linux kernel versions with VMCI enabled.

📋 TL;DR

A vulnerability in the Linux kernel's VMCI driver allows local attackers to potentially leak sensitive information through speculative execution. The issue occurs when user-controlled event data is used as an array index without proper sanitization, potentially exposing kernel memory contents. This affects systems running vulnerable Linux kernel versions with VMCI enabled.

💻 Affected Systems

Products:

Linux kernel

Versions: Kernel versions with vulnerable VMCI driver (specific commit ranges in references)

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ✅ No

Notes: Only vulnerable if VMCI driver is enabled/loaded. Many distributions don't enable VMCI by default.

📦 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Local attacker could leak sensitive kernel memory contents, potentially exposing passwords, encryption keys, or other privileged information through speculative execution side-channels.

🟠

Likely Case

Information disclosure of kernel memory contents to local users, potentially enabling further privilege escalation attacks.

🟢

If Mitigated

Minimal impact with proper kernel hardening and speculative execution mitigations enabled.

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

🏢 Internal Only: MEDIUM - Local users on affected systems could exploit this vulnerability

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access and knowledge of speculative execution techniques. No public exploits known at this time.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions with commits: 58730dfbd4ae01c1b022b0d234a8bf8c02cdfb81, 681967c4ff210e06380acf9b9a1b33ae06e77cbd, 757804e1c599af5d2a7f864c8e8b2842406ff4bb, 8003f00d895310d409b2bf9ef907c56b42a4e0f4, 95ac3e773a1f8da83c4710a720fbfe80055aafae

Vendor Advisory: https://git.kernel.org/stable/c/58730dfbd4ae01c1b022b0d234a8bf8c02cdfb81

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution vendor. 2. Reboot system to load new kernel. 3. Verify VMCI driver is updated.

🔧 Temporary Workarounds

Disable VMCI driver

linux

Prevent loading of vulnerable VMCI driver module

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

🧯 If You Can't Patch

Disable VMCI driver if not required for functionality
Implement strict access controls to limit local user access to affected systems

🔍 How to Verify

Check if Vulnerable:

Check if VMCI module is loaded: lsmod | grep vmci. Check kernel version: uname -r and compare with affected versions.

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is updated and check git commit contains the fix: grep -r 'event_deliver' /proc/kallsyms or check kernel source.

📡 Detection & Monitoring

Log Indicators:

Kernel logs showing VMCI driver loading
System logs showing local privilege escalation attempts

Network Indicators:

Not applicable - local vulnerability

SIEM Query:

source="kernel" AND "vmci" AND ("load" OR "unload")

📊 Metadata

CVE ID: CVE-2024-39499

CVSS v3 Score: 7.1 (HIGH)

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

CWE: CWE-668

Published: July 12, 2024

Last Updated: November 3, 2025

🔗 References

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🔗 Related Vulnerabilities

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