CVE-2023-53259 – A NULL pointer dereference vulnerability in the... (How to Fix)

Q: What is the severity of CVE-2023-53259?

CVE-2023-53259 has a CVSS score of 7.1 (HIGH). A NULL pointer dereference vulnerability in the Linux kernel's VMCI subsystem allows local attackers to cause a general protection fault (GPF) and potentially crash the system. This affects systems with VMCI enabled, typically in virtualized environments. The vulnerability requires local access to exploit.

📋 TL;DR

A NULL pointer dereference vulnerability in the Linux kernel's VMCI subsystem allows local attackers to cause a general protection fault (GPF) and potentially crash the system. This affects systems with VMCI enabled, typically in virtualized environments. The vulnerability requires local access to exploit.

💻 Affected Systems

Products:

Linux kernel

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

Operating Systems: Linux distributions with affected kernel versions

Default Config Vulnerable: ✅ No

Notes: Only vulnerable when VMCI (Virtual Machine Communication Interface) is enabled, typically in VMware or other virtualization environments.

📦 What is this software?

Debian Linux by Debian

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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...

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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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel panic leading to system crash and denial of service, potentially allowing local privilege escalation if combined with other vulnerabilities.

🟠

Likely Case

Local denial of service through kernel crash or instability in virtualized environments.

🟢

If Mitigated

Minimal impact if VMCI is disabled or systems are patched.

🌐 Internet-Facing: LOW - Requires local access, not remotely exploitable.

🏢 Internal Only: MEDIUM - Local users or compromised accounts could crash systems in virtualized environments.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: LOW

Exploitation requires local access and VMCI to be enabled. The vulnerability is triggered through ioctl calls.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Fixed in kernel commits: 055891397f530f9b1b22be38d7eca8b08382941f, 1a726cb47fd204109c767409fa9ca15a96328f14, 91b8e4f61f8f4594ee65368c8d89e6fdc29d3fb1, a3c89e8c69a58f62451c0a75b77fcab25979b897, b4239bfb260d1e6837766c41a0b241d7670f1402

Vendor Advisory: https://git.kernel.org/stable/c/055891397f530f9b1b22be38d7eca8b08382941f

Restart Required: Yes

Instructions:

1. Update to a patched kernel version from your distribution. 2. For Red Hat/CentOS: yum update kernel. 3. For Ubuntu/Debian: apt update && apt upgrade linux-image-*. 4. Reboot the system.

🔧 Temporary Workarounds

Disable VMCI module

linux

Prevent loading of the VMCI kernel module if not required

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

🧯 If You Can't Patch

Disable VMCI module if not required for virtualization functionality
Restrict local user access to systems with VMCI enabled

🔍 How to Verify

Check if Vulnerable:

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

Check Version:

uname -r

Verify Fix Applied:

Check kernel version against patched versions from your distribution vendor. Verify VMCI module functions correctly in virtualization environment.

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
General protection fault errors in dmesg
VMCI-related crash reports

Network Indicators:

None - local exploitation only

SIEM Query:

source="kernel" AND ("general protection fault" OR "GPF" OR "vmci")

📊 Metadata

CVE ID: CVE-2023-53259

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-125

EPSS Score: 0.01% exploit probability (1.2th percentile)

Published: September 15, 2025

Last Updated: January 16, 2026

🔗 References

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