CVE-2023-52696 – This CVE is a NULL pointer dereference vulnerab... (How to Fix)

Q: What is the severity of CVE-2023-52696?

CVE-2023-52696 has a CVSS score of 7.5 (HIGH). This CVE is a NULL pointer dereference vulnerability in the Linux kernel's powerpc/powernv subsystem. The opal_powercap_init() function fails to check if kasprintf() returns NULL, which could cause a kernel panic or system crash. This affects Linux systems running on PowerPC architecture with OPAL firmware.

📋 TL;DR

This CVE is a NULL pointer dereference vulnerability in the Linux kernel's powerpc/powernv subsystem. The opal_powercap_init() function fails to check if kasprintf() returns NULL, which could cause a kernel panic or system crash. This affects Linux systems running on PowerPC architecture with OPAL firmware.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific affected kernel versions not specified in CVE, but patches exist for multiple stable branches

Operating Systems: Linux distributions running on PowerPC/POWER architecture

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems with OPAL (Open Power Abstraction Layer) firmware, typically IBM POWER systems. Requires the powerpc/powernv subsystem to be enabled.

📦 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 →

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 requiring physical access to reboot the system.

🟠

Likely Case

System crash or kernel panic when the vulnerable code path is triggered during power management operations.

🟢

If Mitigated

No impact if the system doesn't use OPAL power capping features or if memory allocation succeeds.

🌐 Internet-Facing: LOW - This requires local access or ability to trigger specific kernel functions.

🏢 Internal Only: MEDIUM - Local users or processes could potentially trigger the vulnerability, causing system instability.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires triggering the specific code path in opal_powercap_init(). Likely requires local access or ability to interact with power management interfaces.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Multiple stable kernel versions with fixes available (see references)

Vendor Advisory: https://git.kernel.org/stable/c/69f95c5e9220f77ce7c540686b056c2b49e9a664

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version. 2. For distributions: Use package manager (apt/yum/dnf) to update kernel. 3. Reboot system to load new kernel.

🔧 Temporary Workarounds

Disable power capping features

linux

If power capping is not required, disable OPAL power capping features

echo 0 > /sys/firmware/opal/powercap/enable

🧯 If You Can't Patch

Restrict access to power management interfaces to trusted users only
Monitor system logs for kernel panic events related to power management

🔍 How to Verify

Check if Vulnerable:

Check kernel version and if running on PowerPC with OPAL. Vulnerable if using unpatched kernel with powerpc/powernv support.

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is updated to one containing the fix commits. Check /proc/version or uname -r.

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
NULL pointer dereference errors in dmesg
System crash/reboot events

Network Indicators:

None - local vulnerability

SIEM Query:

source="kernel" AND ("NULL pointer" OR "kernel panic" OR "powercap")

📊 Metadata

CVE ID: CVE-2023-52696

CVSS v3 Score: 7.5 (HIGH)

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

CWE: CWE-476

Published: May 17, 2024

Last Updated: April 7, 2025

🔗 References

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🔗 Related Vulnerabilities

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