CVE-2023-53084

Q: What is the severity of CVE-2023-53084?

CVE-2023-53084 has a CVSS score of 7.8 (HIGH). This is a use-after-free vulnerability in the Linux kernel's DRM subsystem that occurs when the drm_gem_shmem_mmap() function incorrectly releases a reference in its error path. This allows attackers with local access to potentially crash the system or execute arbitrary code with kernel privileges. It affects Linux systems using the Direct Rendering Manager (DRM) subsystem with shmem-based GEM objects.

7.8 HIGH

📋 TL;DR

This is a use-after-free vulnerability in the Linux kernel's DRM subsystem that occurs when the drm_gem_shmem_mmap() function incorrectly releases a reference in its error path. This allows attackers with local access to potentially crash the system or execute arbitrary code with kernel privileges. It affects Linux systems using the Direct Rendering Manager (DRM) subsystem with shmem-based GEM objects.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific kernel versions containing the vulnerable code (check git commits for exact ranges)

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Requires DRM subsystem with shmem-helper functionality enabled. Most desktop/server Linux distributions are affected if using vulnerable kernel versions.

📦 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...

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⚠️ Risk & Real-World Impact

🔴

Worst Case

Local privilege escalation to kernel-level access leading to full system compromise, data theft, or persistent backdoor installation.

🟠

Likely Case

Kernel panic causing system crash/denial-of-service, potentially leading to data corruption or service disruption.

🟢

If Mitigated

Limited impact due to SELinux/AppArmor restrictions or container isolation preventing kernel access.

🌐 Internet-Facing: LOW - Requires local access to exploit, not directly reachable via network.

🏢 Internal Only: MEDIUM - Local users or compromised applications could exploit this for privilege escalation.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access and knowledge of kernel memory layout. Exploitation depends on specific system configuration and memory state.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions containing the fix commits: 5cfb617967b05f8f27e862c97db1fabd8485f4db and related stable backports

Vendor Advisory: https://git.kernel.org/stable/c/5cfb617967b05f8f27e862c97db1fabd8485f4db

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution's repositories. 2. For custom kernels: Apply the fix commits from kernel git. 3. Reboot system to load new kernel.

🔧 Temporary Workarounds

Disable vulnerable DRM functionality

linux

Remove or disable DRM shmem-helper module if not required

modprobe -r drm_shmem_helper
echo 'blacklist drm_shmem_helper' >> /etc/modprobe.d/blacklist.conf

Restrict local user access

linux

Limit which users can access graphics/DRM functionality

chmod 750 /dev/dri/*
setfacl -m u:root:rw /dev/dri/*

🧯 If You Can't Patch

Implement strict access controls to limit local user privileges
Use containerization to isolate applications from kernel access

🔍 How to Verify

Check if Vulnerable:

Check kernel version and if DRM shmem-helper is loaded: 'lsmod | grep drm_shmem_helper' and 'uname -r'

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is updated and check git commit history includes the fix: 'grep -r "5cfb617967b0" /usr/src/linux'

📡 Detection & Monitoring

Log Indicators:

Kernel oops messages in dmesg
System crashes related to DRM or memory management
Unexpected process terminations with segmentation faults

Network Indicators:

None - local-only vulnerability

SIEM Query:

source="kernel" AND ("Oops" OR "general protection fault" OR "use-after-free") AND ("drm" OR "shmem")

📊 Metadata

CVE ID: CVE-2023-53084

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: 0.02% exploit probability (5.8th percentile)

Published: May 2, 2025

Last Updated: November 12, 2025

📋 TL;DR

💻 Affected Systems

📦 What is this software?

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

⚠️ Risk & Real-World Impact

Worst Case

Likely Case

If Mitigated

🎯 Exploit Status

🛠️ Fix & Mitigation

✅ Official Fix

Instructions:

🔧 Temporary Workarounds

Disable vulnerable DRM functionality

Restrict local user access

🧯 If You Can't Patch

🔍 How to Verify

Check if Vulnerable:

Check Version:

Verify Fix Applied:

📡 Detection & Monitoring

Log Indicators:

Network Indicators:

SIEM Query:

📊 Metadata

🔗 References

📤 Share & Export

🔗 Related Vulnerabilities