CVE-2023-52698 – A memory leak vulnerability exists in the Linux... (How to Fix)

Q: What is the severity of CVE-2023-52698?

CVE-2023-52698 has a CVSS score of 5.5 (MEDIUM). A memory leak vulnerability exists in the Linux kernel's CALIPSO/IPv6 labeling subsystem when IPv6 support is disabled at boot. This causes kernel memory allocation without proper cleanup, leading to gradual memory exhaustion. Systems running affected Linux kernel versions with IPv6 disabled are vulnerable.

📋 TL;DR

A memory leak vulnerability exists in the Linux kernel's CALIPSO/IPv6 labeling subsystem when IPv6 support is disabled at boot. This causes kernel memory allocation without proper cleanup, leading to gradual memory exhaustion. Systems running affected Linux kernel versions with IPv6 disabled are vulnerable.

💻 Affected Systems

Products:

Linux Kernel

Versions: Specific affected versions not explicitly listed, but references indicate stable kernel patches from 5.10 through 6.6 branches

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ✅ No

Notes: Only vulnerable when IPv6 is disabled at boot via 'ipv6.disable=1' kernel parameter

📦 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Sustained exploitation could lead to kernel memory exhaustion, causing system instability, denial of service, or potential kernel crashes.

🟠

Likely Case

Gradual memory consumption over time leading to performance degradation and potential system instability.

🟢

If Mitigated

Minimal impact with proper monitoring and memory limits in place.

🌐 Internet-Facing: LOW - Requires local access or specific network configuration to trigger.

🏢 Internal Only: MEDIUM - Internal users or processes could trigger the memory leak, affecting system stability.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: NO

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires ability to trigger netlabel operations with IPv6 disabled; discovered via fuzzing (Syzkaller)

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Patched in stable kernel versions via commits referenced in CVE

Vendor Advisory: https://git.kernel.org/stable/c/321b3a5592c8a9d6b654c7c64833ea67dbb33149

Restart Required: Yes

Instructions:

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

🔧 Temporary Workarounds

Enable IPv6 Support

linux

Remove 'ipv6.disable=1' kernel parameter to avoid triggering the vulnerable code path

Edit /etc/default/grub or bootloader config
Remove 'ipv6.disable=1' from GRUB_CMDLINE_LINUX
Run 'update-grub' (Debian/Ubuntu) or 'grub2-mkconfig' (RHEL/Fedora)
Reboot system

🧯 If You Can't Patch

Monitor kernel memory usage closely for unusual increases
Consider disabling netlabel/CALIPSO functionality if not required

🔍 How to Verify

Check if Vulnerable:

Check if IPv6 is disabled and kernel version is unpatched: 'cat /proc/cmdline | grep ipv6.disable=1' and 'uname -r'

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is updated and check for memory leaks using tools like 'slabtop' or monitoring /proc/meminfo

📡 Detection & Monitoring

Log Indicators:

Kernel oom-killer messages
Memory allocation failures in dmesg
Increasing slab memory usage

Network Indicators:

Unusual netlabel traffic patterns

SIEM Query:

source="kernel" AND ("out of memory" OR "slab" OR "kmalloc")

📊 Metadata

CVE ID: CVE-2023-52698

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

CWE: CWE-401

Published: May 17, 2024

Last Updated: January 7, 2025

🔗 References

📤 Share & Export

📄 Export Markdown 📋 Export JSON

🔗 Related Vulnerabilities

If you're affected by CVE-2023-52698, you might also want to check these: