CVE-2023-33951 – A race condition vulnerability in the Linux ker... (How to Fix)

Q: What is the severity of CVE-2023-33951?

CVE-2023-33951 has a CVSS score of 6.7 (MEDIUM). A race condition vulnerability in the Linux kernel's vmwgfx driver allows improper handling of GEM objects due to insufficient locking. This enables a local privileged user to leak kernel memory information. Only systems with the vulnerable driver loaded are affected.

📋 TL;DR

A race condition vulnerability in the Linux kernel's vmwgfx driver allows improper handling of GEM objects due to insufficient locking. This enables a local privileged user to leak kernel memory information. Only systems with the vulnerable driver loaded are affected.

💻 Affected Systems

Products:

Linux kernel

Versions: Kernel versions with vulnerable vmwgfx driver (specific versions vary by distribution)

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Only vulnerable when vmwgfx driver is loaded (typically on VMware virtual machines or systems with VMware graphics)

📦 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel memory disclosure leading to potential privilege escalation or system compromise through information disclosure that could reveal sensitive data or facilitate further attacks.

🟠

Likely Case

Local information disclosure of kernel memory contents by a privileged user, potentially exposing sensitive system information.

🟢

If Mitigated

Minimal impact if proper access controls restrict local privileged users and the driver isn't loaded.

🌐 Internet-Facing: LOW - Requires local access and privileged user context.

🏢 Internal Only: MEDIUM - Internal privileged users could exploit this for information disclosure.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local privileged access and knowledge of race condition exploitation techniques

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Varies by distribution - check Red Hat advisories for specific kernel versions

Vendor Advisory: https://access.redhat.com/errata/RHSA-2023:6583

Restart Required: Yes

Instructions:

1. Update kernel package using distribution's package manager. 2. For RHEL/CentOS: 'yum update kernel'. 3. For Ubuntu/Debian: 'apt update && apt upgrade linux-image'. 4. Reboot system to load patched kernel.

🔧 Temporary Workarounds

Disable vmwgfx driver

linux

Prevent loading of vulnerable driver module

echo 'blacklist vmwgfx' >> /etc/modprobe.d/blacklist.conf
rmmod vmwgfx

🧯 If You Can't Patch

Restrict local privileged user access to essential personnel only
Implement strict access controls and monitoring for local privileged accounts

🔍 How to Verify

Check if Vulnerable:

Check kernel version against patched versions in vendor advisories: 'uname -r'

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version after update and reboot: 'uname -r' matches patched version

📡 Detection & Monitoring

Log Indicators:

Kernel oops messages
Driver loading/unloading anomalies
Privileged user activity patterns

Network Indicators:

None - local exploit only

SIEM Query:

source="kernel" AND ("vmwgfx" OR "GEM") AND ("error" OR "warning" OR "oops")

📊 Metadata

CVE ID: CVE-2023-33951

CVSS v3 Score: 6.7 (MEDIUM)

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

CWE: CWE-413

Published: July 24, 2023

Last Updated: February 18, 2026

🔗 References

https://access.redhat.com/errata/RHSA-2023:6583 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:6901 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:7077 Third Party Advisory
https://access.redhat.com/errata/RHSA-2024:1404
https://access.redhat.com/errata/RHSA-2024:4823
https://access.redhat.com/errata/RHSA-2024:4831
https://access.redhat.com/security/cve/CVE-2023-33951 Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2218195 Issue Tracking,Patch
https://www.zerodayinitiative.com/advisories/ZDI-CAN-20110/ Third Party Advisory,VDB Entry
https://access.redhat.com/errata/RHSA-2023:6583 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:6901 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:7077 Third Party Advisory
https://access.redhat.com/errata/RHSA-2024:1404
https://access.redhat.com/errata/RHSA-2024:4823
https://access.redhat.com/errata/RHSA-2024:4831
https://access.redhat.com/security/cve/CVE-2023-33951 Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2218195 Issue Tracking,Patch
https://www.zerodayinitiative.com/advisories/ZDI-CAN-20110/ Third Party Advisory,VDB Entry

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