CVE-2023-53485 – This is an array index out-of-bounds vulnerabil... (How to Fix)

Q: What is the severity of CVE-2023-53485?

CVE-2023-53485 has a CVSS score of 7.8 (HIGH). This is an array index out-of-bounds vulnerability in the JFS filesystem implementation in the Linux kernel. An attacker could trigger this bug to cause a kernel panic (denial of service) or potentially execute arbitrary code with kernel privileges. All Linux systems using the JFS filesystem are affected.

📋 TL;DR

This is an array index out-of-bounds vulnerability in the JFS filesystem implementation in the Linux kernel. An attacker could trigger this bug to cause a kernel panic (denial of service) or potentially execute arbitrary code with kernel privileges. All Linux systems using the JFS filesystem are affected.

💻 Affected Systems

Products:

Linux kernel

Versions: Kernel versions before the fix commits (specific versions vary by distribution)

Operating Systems: Linux distributions with JFS filesystem support

Default Config Vulnerable: ✅ No

Notes: Only affects systems using JFS filesystem. Most Linux distributions don't use JFS by default, but it's available as an optional filesystem.

📦 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 →

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, or potential kernel memory corruption that could lead to arbitrary code execution with kernel privileges.

🟠

Likely Case

Kernel panic and system crash (denial of service) when the bug is triggered through filesystem operations.

🟢

If Mitigated

System remains stable with proper patching; unpatched systems risk crashes when specific JFS operations are performed.

🌐 Internet-Facing: LOW - Requires local filesystem access or ability to mount JFS partitions, not typically exposed directly to internet.

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

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires ability to perform specific JFS filesystem operations. Discovered via syzkaller fuzzing, suggesting it's triggerable but not widely weaponized.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Fixed in kernel commits: 0d9e678a8291, 39f6292d7595, 4e302336d5ca, 53b0a362aca2, 6e7d9d76e565

Vendor Advisory: https://git.kernel.org/stable/c/0d9e678a82915633b99603f744e7735d1a673d72

Restart Required: Yes

Instructions:

1. Update Linux kernel to version containing the fix. 2. Check your distribution's security advisories for specific patched kernel versions. 3. Reboot system after kernel update.

🔧 Temporary Workarounds

Disable JFS filesystem

linux

Prevent loading of JFS kernel module to eliminate attack surface

echo 'install jfs /bin/false' >> /etc/modprobe.d/disable-jfs.conf
rmmod jfs 2>/dev/null || true

Blacklist JFS module

linux

Prevent JFS module from being loaded at boot

echo 'blacklist jfs' >> /etc/modprobe.d/blacklist-jfs.conf

🧯 If You Can't Patch

Avoid using JFS filesystem for any partitions
Restrict user access to JFS-mounted directories and filesystem operations

🔍 How to Verify

Check if Vulnerable:

Check if JFS module is loaded: lsmod | grep jfs. If loaded and kernel version is unpatched, system is vulnerable.

Check Version:

uname -r

Verify Fix Applied:

Check kernel version against distribution's patched versions, and verify JFS operations don't cause crashes.

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
UBSAN array-index-out-of-bounds errors in kernel logs
System crashes during filesystem operations

SIEM Query:

source="kernel" AND ("UBSAN" OR "array-index-out-of-bounds" OR "jfs_dmap" OR "dbAllocDmapLev")

📊 Metadata

CVE ID: CVE-2023-53485

CVSS v3 Score: 7.8 (HIGH)

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

CWE: CWE-129

EPSS Score: 0.02% exploit probability (5.7th percentile)

Published: October 1, 2025

Last Updated: January 23, 2026

🔗 References

📤 Share & Export

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🔗 Related Vulnerabilities

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