CVE-2023-53457 – A NULL pointer dereference vulnerability exists... (How to Fix)

Q: What is the severity of CVE-2023-53457?

CVE-2023-53457 has a CVSS score of 5.5 (MEDIUM). A NULL pointer dereference vulnerability exists in the JFS filesystem implementation in the Linux kernel. When txBegin is called on a read-only mounted filesystem, it can cause a kernel panic or system crash. This affects Linux systems using the JFS filesystem with read-only mounts.

📋 TL;DR

A NULL pointer dereference vulnerability exists in the JFS filesystem implementation in the Linux kernel. When txBegin is called on a read-only mounted filesystem, it can cause a kernel panic or system crash. This affects Linux systems using the JFS filesystem with read-only mounts.

💻 Affected Systems

Products:

Linux Kernel

Versions: Specific kernel versions with vulnerable JFS implementation (check git commits for exact ranges)

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ✅ No

Notes: Only affects systems using JFS filesystem with read-only mounts. JFS is not a default filesystem on most Linux distributions.

📦 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...

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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 →

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 causing data loss or system instability.

🟠

Likely Case

System crash or kernel panic when accessing JFS filesystems mounted as read-only, resulting in denial of service.

🟢

If Mitigated

Minimal impact if systems don't use JFS filesystems or have proper kernel patches applied.

🌐 Internet-Facing: LOW - Requires local filesystem access and specific JFS configuration.

🏢 Internal Only: MEDIUM - Internal systems using JFS with read-only mounts could experience crashes affecting services.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access to trigger the condition. Discovered via syzkaller fuzzing.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions with commits: 1b4c144767736221cad92c132f72b3c6ed06a0ea, 2a3f20efe6c901d4c0871cfd1d8c65e2ade71fc1, 3e5eb6c5ecd8ddb9cfea751cf30f9e23eac97ca3, 3e94d0d378d2754b26fc54b429582553f7b53e15, 47cfdc338d674d38f4b2f22b7612cc6a2763ba27

Vendor Advisory: https://git.kernel.org/stable/c/1b4c144767736221cad92c132f72b3c6ed06a0ea

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version. 2. Check distribution-specific security advisories. 3. Reboot system after kernel update.

🔧 Temporary Workarounds

Avoid JFS read-only mounts

linux

Do not mount JFS filesystems as read-only until patched

# Check current mounts: mount | grep jfs
# Remount as read-write if possible: mount -o remount,rw /mount/point

Disable JFS module

linux

Prevent JFS module from loading if not needed

# Blacklist JFS module: echo 'blacklist jfs' >> /etc/modprobe.d/blacklist.conf
# Rebuild initramfs if needed

🧯 If You Can't Patch

Avoid using JFS filesystem for critical systems
Ensure JFS mounts are read-write, not read-only

🔍 How to Verify

Check if Vulnerable:

Check kernel version and if JFS is in use: uname -r && lsmod | grep jfs && mount | grep jfs

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes the fix commits and test JFS read-only mount functionality

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages in /var/log/kern.log or dmesg
NULL pointer dereference errors
System crash/reboot events

Network Indicators:

None - local filesystem vulnerability

SIEM Query:

Search for: 'kernel panic', 'NULL pointer dereference', 'JFS', 'txBegin' in system logs

📊 Metadata

CVE ID: CVE-2023-53457

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-476

EPSS Score: 0.02% exploit probability (5.5th percentile)

Published: October 1, 2025

Last Updated: January 16, 2026

🔗 References

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