CVE-2024-47723 – This vulnerability in the Linux kernel's JFS fi... (How to Fix)

Q: What is the severity of CVE-2024-47723?

CVE-2024-47723 has a CVSS score of 7.1 (HIGH). This vulnerability in the Linux kernel's JFS filesystem allows out-of-bounds memory access when processing corrupted disk images. Attackers could potentially crash the system or execute arbitrary code by mounting a maliciously crafted JFS filesystem. All Linux systems using JFS filesystems are affected.

📋 TL;DR

This vulnerability in the Linux kernel's JFS filesystem allows out-of-bounds memory access when processing corrupted disk images. Attackers could potentially crash the system or execute arbitrary code by mounting a maliciously crafted JFS filesystem. All Linux systems using JFS filesystems are affected.

💻 Affected Systems

Products:

Linux kernel with JFS filesystem support

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

Operating Systems: Linux distributions with JFS support enabled

Default Config Vulnerable: ✅ No

Notes: Only vulnerable if JFS filesystem support is compiled into the kernel or loaded as a module, and when mounting JFS filesystems.

📦 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel panic leading to denial of service, or potential privilege escalation to kernel-level code execution.

🟠

Likely Case

System crash or kernel panic when mounting corrupted JFS filesystems, causing denial of service.

🟢

If Mitigated

Limited to denial of service if kernel hardening features like KASLR and SMAP/SMEP are enabled.

🌐 Internet-Facing: LOW - Requires mounting a malicious JFS filesystem, unlikely via typical internet-facing services.

🏢 Internal Only: MEDIUM - Internal attackers could exploit by mounting crafted filesystems on shared storage or via removable media.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires ability to mount a malicious JFS filesystem, typically needing local access or ability to supply filesystem images to mount operations.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions containing commits 0338e66cba27, 128d5cfdcf84, 5ad6284c8d43, 6ce8b6ab44a8, or 96855f40e152

Vendor Advisory: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution. 2. Reboot system to load new kernel. 3. Verify JFS module is updated if using module.

🔧 Temporary Workarounds

Disable JFS filesystem support

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

Restrict filesystem mounting

linux

Limit who can mount filesystems using mount permissions and namespaces

chmod 700 /bin/mount
chmod 700 /sbin/mount.jfs

🧯 If You Can't Patch

Avoid using JFS filesystems; migrate to alternative filesystems like ext4 or XFS.
Implement strict access controls on mount operations and limit users who can mount filesystems.

🔍 How to Verify

Check if Vulnerable:

Check if JFS module is loaded: lsmod | grep jfs. Check kernel version against distribution security advisories.

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes fix commits: grep -E '0338e66cba27|128d5cfdcf84|5ad6284c8d43|6ce8b6ab44a8|96855f40e152' /proc/version_signature

📡 Detection & Monitoring

Log Indicators:

Kernel oops messages mentioning dbNextAG, diAlloc, or JFS
System crashes when mounting filesystems
Unexpected kernel panics

Network Indicators:

N/A - local exploitation only

SIEM Query:

source="kernel" AND ("JFS" OR "dbNextAG" OR "diAlloc" OR "out-of-bounds")

📊 Metadata

CVE ID: CVE-2024-47723

CVSS v3 Score: 7.1 (HIGH)

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

CWE: CWE-125

Published: October 21, 2024

Last Updated: November 3, 2025

🔗 References

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🔗 Related Vulnerabilities

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