CVE-2023-52923 – This CVE addresses a vulnerability in the Linux... (How to Fix)

Q: What is the severity of CVE-2023-52923?

CVE-2023-52923 has a CVSS score of 5.5 (MEDIUM). This CVE addresses a vulnerability in the Linux kernel's netfilter nf_tables subsystem where improper garbage collection handling could lead to use-after-free conditions. Systems running affected Linux kernel versions with nf_tables enabled are vulnerable. The issue allows local attackers to potentially escalate privileges or cause denial of service.

📋 TL;DR

This CVE addresses a vulnerability in the Linux kernel's netfilter nf_tables subsystem where improper garbage collection handling could lead to use-after-free conditions. Systems running affected Linux kernel versions with nf_tables enabled are vulnerable. The issue allows local attackers to potentially escalate privileges or cause denial of service.

💻 Affected Systems

Products:

Linux Kernel

Versions: Specific affected versions not explicitly stated in CVE description; typically affects versions before the fix commits listed in references.

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Requires nf_tables subsystem to be enabled/loaded. Most modern Linux distributions have this enabled by default for firewall functionality.

📦 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 →

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 privilege escalation to root, kernel panic leading to system crash, or arbitrary code execution in kernel context.

🟠

Likely Case

Local denial of service through kernel panic or system instability, potential information disclosure from kernel memory.

🟢

If Mitigated

Minimal impact with proper kernel hardening, SELinux/AppArmor enforcement, and restricted user privileges.

🌐 Internet-Facing: LOW - This is primarily a local vulnerability requiring access to the system.

🏢 Internal Only: MEDIUM - Internal users with shell access could exploit this for privilege escalation or DoS attacks.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access and knowledge of kernel exploitation techniques. The vulnerability involves complex garbage collection timing issues.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions containing commits: 146c76866795553dbc19998f36718d7986ad302b, 479a2cf5259347d6a1f658b0f791d27a34908e91, c357648929c8dff891502349769aafb8f0452bc2, cb4d00b563675ba8ff6ef94b077f58d816f68ba3, df650d6a4bf47248261b61ef6b174d7c54034d15

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

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution vendor. 2. Reboot system to load new kernel. 3. Verify kernel version matches patched release.

🔧 Temporary Workarounds

Disable nf_tables module

linux

Unload nf_tables kernel module to remove attack surface (will break firewall functionality)

sudo rmmod nf_tables

Blacklist nf_tables module

linux

Prevent nf_tables from loading at boot

echo 'blacklist nf_tables' | sudo tee /etc/modprobe.d/blacklist-nftables.conf

🧯 If You Can't Patch

Restrict local user access through proper privilege separation and least privilege principles.
Implement kernel hardening measures like SELinux/AppArmor to limit impact of potential exploitation.

🔍 How to Verify

Check if Vulnerable:

Check if nf_tables module is loaded: lsmod | grep nf_tables && check kernel version against patched releases.

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes the fix commits or is newer than patched version from your distribution.

📡 Detection & Monitoring

Log Indicators:

Kernel oops messages in /var/log/kern.log or dmesg
System crashes or unexpected reboots
Failed module operations related to nf_tables

Network Indicators:

None - this is a local kernel vulnerability

SIEM Query:

source="kern.log" AND ("Oops" OR "general protection fault" OR "kernel panic") AND ("nf_tables" OR "netfilter")

📊 Metadata

CVE ID: CVE-2023-52923

CVSS v3 Score: 5.5 (MEDIUM)

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

EPSS Score: 0.06% exploit probability (17.3th percentile)

Published: January 20, 2025

Last Updated: October 15, 2025

🔗 References

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