CVE-2023-52854 – A use-after-free vulnerability in the Linux ker... (How to Fix)

Q: What is the severity of CVE-2023-52854?

CVE-2023-52854 has a CVSS score of 7.8 (HIGH). A use-after-free vulnerability in the Linux kernel's padata subsystem allows local attackers to potentially crash the system or execute arbitrary code with kernel privileges. This affects Linux systems using the padata parallelization framework, particularly under high load conditions where softirq processing is delayed.

📋 TL;DR

A use-after-free vulnerability in the Linux kernel's padata subsystem allows local attackers to potentially crash the system or execute arbitrary code with kernel privileges. This affects Linux systems using the padata parallelization framework, particularly under high load conditions where softirq processing is delayed.

💻 Affected Systems

Products:

Linux Kernel

Versions: Specific affected versions not explicitly stated in CVE; check kernel commit history for vulnerable padata.c implementations

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ✅ No

Notes: Only vulnerable when padata subsystem is actively used (e.g., by pcrypt module or custom implementations). Many systems may not use padata 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 kernel-level code execution leading to complete system compromise, data theft, or persistent backdoor installation.

🟠

Likely Case

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

🟢

If Mitigated

Limited impact if proper access controls prevent local user access or if padata functionality is not in use.

🌐 Internet-Facing: LOW - Requires local access to exploit; not directly exploitable over network.

🏢 Internal Only: MEDIUM - Local users or processes could exploit this, but requires specific padata usage patterns and high load conditions.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: HIGH

Exploitation requires local access, specific padata usage patterns, and high system load conditions to trigger timing issues.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions with commits: 0dd34a7ad395dbcf6ae60e48e9786050e25b9bc5, 1734a79e951914f1db2c65e635012a35db1c674b, 1e901bcb8af19416b65f5063a4af7996e5a51d7f, 41aad9d6953984d134fc50f631f24ef476875d4d, 7ddc21e317b360c3444de3023bcc83b85fabae2f

Vendor Advisory: https://git.kernel.org/stable/c/0dd34a7ad395dbcf6ae60e48e9786050e25b9bc5

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 padata functionality

linux

Remove or disable modules using padata subsystem if not required

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

Limit local user access

linux

Restrict local user accounts and monitor for suspicious activity

Review /etc/passwd and /etc/shadow for unnecessary accounts
Implement SELinux/AppArmor policies

🧯 If You Can't Patch

Monitor system logs for kernel panics or unusual padata-related errors
Implement strict access controls to prevent unauthorized local user access

🔍 How to Verify

Check if Vulnerable:

Check if padata modules are loaded: lsmod | grep -E '(padata|pcrypt)' and check kernel version against patched releases

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes the fix commits: uname -r and check with distribution vendor for patch status

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
Use-after-free warnings in dmesg
Padata subsystem errors

Network Indicators:

None - local exploitation only

SIEM Query:

source="kernel" AND ("use-after-free" OR "padata" OR "kernel panic")

📊 Metadata

CVE ID: CVE-2023-52854

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

Published: May 21, 2024

Last Updated: February 3, 2025

🔗 References

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🔗 Related Vulnerabilities

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