CVE-2024-56597 – This vulnerability in the Linux kernel's JFS fi... (How to Fix)

Q: What is the severity of CVE-2024-56597?

CVE-2024-56597 has a CVSS score of 7.1 (HIGH). This vulnerability in the Linux kernel's JFS filesystem allows a local attacker to trigger a shift-out-of-bounds error in the dbSplit function when dmt_budmin is negative, potentially leading to kernel memory corruption. It affects systems using the JFS filesystem with vulnerable kernel versions. Exploitation requires local access to the system.

📋 TL;DR

This vulnerability in the Linux kernel's JFS filesystem allows a local attacker to trigger a shift-out-of-bounds error in the dbSplit function when dmt_budmin is negative, potentially leading to kernel memory corruption. It affects systems using the JFS filesystem with vulnerable kernel versions. Exploitation requires local access to the system.

💻 Affected Systems

Products:

Linux kernel with JFS filesystem support

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

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ✅ No

Notes: Only vulnerable if JFS filesystem is mounted or in use. Many distributions don't enable JFS by default.

📦 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel panic or system crash leading to denial of service, with potential for local privilege escalation if combined with other vulnerabilities.

🟠

Likely Case

System crash or kernel panic causing denial of service on affected systems.

🟢

If Mitigated

Minimal impact if JFS filesystem is not in use or proper access controls limit local user privileges.

🌐 Internet-Facing: LOW - Requires local access to exploit, not directly reachable from network.

🏢 Internal Only: MEDIUM - Local users or compromised accounts could exploit this to cause system instability.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires local access and knowledge of triggering the specific condition in JFS filesystem operations.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Fixed in kernel commits: 51a203470f502a64a3da8dcea51c4748e8267a6c, 52756a57e978e2706543a254f88f266cc6702f36, 6676034aa753aa448beb30dbd75630927ba7cd96, a5f5e4698f8abbb25fe4959814093fb5bfa1aa9d, bbb24ce7f06ef9b7c05beb9340787cbe9fd3d08e

Vendor Advisory: https://git.kernel.org/stable/c/51a203470f502a64a3da8dcea51c4748e8267a6c

Restart Required: Yes

Instructions:

1. Update Linux kernel to version containing the fix commits. 2. Check distribution-specific security advisories. 3. Reboot system after kernel update.

🔧 Temporary Workarounds

Disable JFS filesystem

linux

Prevent loading of JFS kernel module to eliminate attack surface

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

Restrict local user access

linux

Limit which users can execute privileged operations on JFS filesystems

🧯 If You Can't Patch

Avoid using JFS filesystem for critical systems
Implement strict access controls to limit local user privileges

🔍 How to Verify

Check if Vulnerable:

Check if JFS module is loaded: lsmod | grep jfs. Check kernel version against patched versions.

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes fix commits. Check that JFS operations don't cause crashes.

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
JFS-related error messages in dmesg
System crash logs

SIEM Query:

source="kernel" AND ("panic" OR "JFS" OR "dbSplit")

📊 Metadata

CVE ID: CVE-2024-56597

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: December 27, 2024

Last Updated: November 3, 2025

🔗 References

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🔗 Related Vulnerabilities

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