CVE-2023-53241 – This CVE describes a memory leak vulnerability ... (How to Fix)

Q: What is the severity of CVE-2023-53241?

CVE-2023-53241 has a CVSS score of 5.5 (MEDIUM). This CVE describes a memory leak vulnerability in the Linux kernel's NFS server (nfsd) component. When processing certain NFS operations with errors, the kernel fails to properly release allocated memory, potentially leading to resource exhaustion. Systems running affected Linux kernel versions with NFS server enabled are vulnerable.

📋 TL;DR

This CVE describes a memory leak vulnerability in the Linux kernel's NFS server (nfsd) component. When processing certain NFS operations with errors, the kernel fails to properly release allocated memory, potentially leading to resource exhaustion. Systems running affected Linux kernel versions with NFS server enabled are vulnerable.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific affected versions not explicitly stated in CVE description; check kernel commit history for exact ranges

Operating Systems: Linux distributions with affected kernel versions

Default Config Vulnerable: ✅ No

Notes: Only vulnerable when NFS server (nfsd) is enabled and in use. Systems not using NFS server are not affected.

📦 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Sustained exploitation could cause kernel memory exhaustion leading to system instability, denial of service, or potential kernel panic/crash.

🟠

Likely Case

Memory leak gradually consumes kernel resources, potentially causing performance degradation or service disruption over time.

🟢

If Mitigated

With proper monitoring and resource limits, impact is limited to potential performance issues that can be detected and addressed.

🌐 Internet-Facing: MEDIUM - NFS servers exposed to untrusted networks could be targeted to trigger memory exhaustion attacks.

🏢 Internal Only: LOW - Internal NFS clients would need to intentionally trigger the error condition to exploit.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires ability to trigger specific NFS operations with error conditions. Requires NFS client access to the server.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions containing commits: 15a8b55dbb1ba154d82627547c5761cac884d810, 3d0dcada384af22dec764c8374a2997870ec86ae, 65a33135e91e6dd661ecdf1194b9d90c49ae3570, b11d8162c24af4a351d21e2c804d25ca493305e3, b623a8e5d38a69a3ef8644acb1030dd7c7bc28b3

Vendor Advisory: https://git.kernel.org/stable/c/15a8b55dbb1ba154d82627547c5761cac884d810

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 after reboot.

🔧 Temporary Workarounds

Disable NFS server

Linux

If NFS server functionality is not required, disable it to eliminate the vulnerability.

systemctl stop nfs-server
systemctl disable nfs-server

🧯 If You Can't Patch

Monitor kernel memory usage and system logs for signs of memory exhaustion
Implement network segmentation to restrict NFS access to trusted clients only

🔍 How to Verify

Check if Vulnerable:

Check if NFS server is running and compare kernel version against patched versions from your distribution.

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version after update matches patched version and test NFS operations.

📡 Detection & Monitoring

Log Indicators:

Kernel oom-killer messages
Memory allocation failures in kernel logs
NFS error messages

Network Indicators:

Unusual NFS request patterns triggering errors

SIEM Query:

source="kernel" AND ("out of memory" OR "oom-killer" OR "nfsd" AND "error")

📊 Metadata

CVE ID: CVE-2023-53241

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

EPSS Score: 0.01% exploit probability (1.1th percentile)

Published: September 15, 2025

Last Updated: January 14, 2026

🔗 References

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