CVE-2023-53276 – This is a memory leak vulnerability in the Linu... (How to Fix)

Q: What is the severity of CVE-2023-53276?

CVE-2023-53276 has a CVSS score of 5.5 (MEDIUM). This is a memory leak vulnerability in the Linux kernel's UBIFS filesystem when creating temporary files in encrypted directories. The kernel fails to free allocated memory after copying a filename, causing gradual memory exhaustion over time. This affects Linux systems using UBIFS with encrypted directories.

📋 TL;DR

This is a memory leak vulnerability in the Linux kernel's UBIFS filesystem when creating temporary files in encrypted directories. The kernel fails to free allocated memory after copying a filename, causing gradual memory exhaustion over time. This affects Linux systems using UBIFS with encrypted directories.

💻 Affected Systems

Products:

Linux Kernel

Versions: Specific affected kernel versions not explicitly stated in CVE; check git commits for exact ranges

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ✅ No

Notes: Only affects systems with UBIFS filesystem and encrypted directories; requires both features to be configured and used.

📦 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...

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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 →

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, crashes, or denial of service through resource depletion.

🟠

Likely Case

Gradual memory consumption over time when tmpfiles are created in encrypted UBIFS directories, potentially degrading system performance.

🟢

If Mitigated

Minimal impact with proper monitoring and memory limits in place; memory would eventually be reclaimed on system restart.

🌐 Internet-Facing: LOW - Requires local filesystem access and specific UBIFS configuration; not directly exploitable over network.

🏢 Internal Only: MEDIUM - Local users or processes creating tmpfiles in encrypted UBIFS directories could gradually consume kernel memory.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires local access and ability to create tmpfiles in encrypted UBIFS directories; memory leak occurs gradually with repeated operations.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Check kernel git commits: 107d481642c356a5668058066360fc473911e628 and related

Vendor Advisory: https://git.kernel.org/stable/c/107d481642c356a5668058066360fc473911e628

Restart Required: Yes

Instructions:

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

🔧 Temporary Workarounds

Disable UBIFS encrypted directories

all

Prevent use of encrypted directories on UBIFS filesystem to avoid triggering the vulnerability

# Configure system to avoid creating encrypted directories on UBIFS
# Review and modify fscrypt configuration

Monitor kernel memory usage

all

Implement monitoring for unusual kernel memory consumption patterns

# Monitor with: cat /proc/meminfo | grep Slab
# Check slab memory growth over time

🧯 If You Can't Patch

Implement strict monitoring of kernel memory usage and alert on abnormal slab growth
Restrict user access to create tmpfiles in encrypted UBIFS directories where possible

🔍 How to Verify

Check if Vulnerable:

Check kernel version and UBIFS configuration; test by creating tmpfiles in encrypted UBIFS directories while monitoring slab memory with 'cat /proc/meminfo | grep Slab'

Check Version:

uname -r

Verify Fix Applied:

After patching, verify kernel version is updated and test tmpfile creation no longer causes increasing slab memory that isn't reclaimed

📡 Detection & Monitoring

Log Indicators:

Kernel oom-killer events
System logs showing memory pressure warnings
UBIFS error messages related to memory allocation

Network Indicators:

None - local filesystem vulnerability

SIEM Query:

source="kernel" AND ("oom-killer" OR "slab" OR "memory" AND "pressure")

📊 Metadata

CVE ID: CVE-2023-53276

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 (0.9th percentile)

Published: September 16, 2025

Last Updated: January 14, 2026

🔗 References

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