CVE-2025-38697

Q: What is the severity of CVE-2025-38697?

CVE-2025-38697 has a CVSS score of 7.8 (HIGH). This CVE describes an out-of-bounds read vulnerability in the JFS filesystem implementation in the Linux kernel. An attacker could exploit filesystem metadata corruption to trigger this vulnerability, potentially leading to kernel memory disclosure or system instability. All Linux systems using JFS filesystems are affected.

7.8 HIGH

📋 TL;DR

This CVE describes an out-of-bounds read vulnerability in the JFS filesystem implementation in the Linux kernel. An attacker could exploit filesystem metadata corruption to trigger this vulnerability, potentially leading to kernel memory disclosure or system instability. All Linux systems using JFS filesystems are affected.

💻 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 affected kernel versions

Default Config Vulnerable: ✅ No

Notes: Only vulnerable when JFS filesystem is in use. Most distributions don't use JFS by default.

📦 What is this software?

Debian Linux by Debian

View all CVEs affecting Debian Linux →

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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⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel panic leading to denial of service, or potential information disclosure from kernel memory

🟠

Likely Case

System crash or instability when accessing corrupted JFS filesystems

🟢

If Mitigated

No impact if JFS filesystems are not used or if filesystem metadata is not corrupted

🌐 Internet-Facing: LOW - Requires local filesystem access or ability to corrupt filesystem metadata

🏢 Internal Only: MEDIUM - Local users or processes with filesystem access could potentially trigger the vulnerability

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: HIGH

Exploitation requires ability to corrupt filesystem metadata or trigger the specific code path in dbAllocAG

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Linux kernel with commits 1467a75819e41341cd5ebd16faa2af1ca3c8f4fe and related fixes

Vendor Advisory: https://git.kernel.org/stable/c/1467a75819e41341cd5ebd16faa2af1ca3c8f4fe

Restart Required: Yes

Instructions:

1. Update Linux kernel to version containing the fix commits. 2. For distributions: Use package manager (apt/yum/dnf) to update kernel. 3. Reboot system to load new kernel.

🔧 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

Avoid JFS usage

linux

Do not mount or use JFS filesystems

umount /dev/[jfs-partition]

🧯 If You Can't Patch

Ensure no JFS filesystems are mounted or in use
Implement strict access controls to prevent unauthorized filesystem access

🔍 How to Verify

Check if Vulnerable:

Check if JFS filesystem is in use: 'mount | grep -i jfs' and 'lsmod | grep jfs'

Check Version:

uname -r

Verify Fix Applied:

Check kernel version contains fix commits or is newer than vulnerable versions

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
JFS-related error messages in dmesg
Filesystem corruption warnings

Network Indicators:

None - local filesystem vulnerability

SIEM Query:

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

📊 Metadata

CVE ID: CVE-2025-38697

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: 0.01% exploit probability (2.4th percentile)

Published: September 4, 2025

Last Updated: January 26, 2026

📋 TL;DR

💻 Affected Systems

📦 What is this software?

Debian Linux by Debian

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

⚠️ Risk & Real-World Impact

Worst Case

Likely Case

If Mitigated

🎯 Exploit Status

🛠️ Fix & Mitigation

✅ Official Fix

Instructions:

🔧 Temporary Workarounds

Disable JFS filesystem

Avoid JFS usage

🧯 If You Can't Patch

🔍 How to Verify

Check if Vulnerable:

Check Version:

Verify Fix Applied:

📡 Detection & Monitoring

Log Indicators:

Network Indicators:

SIEM Query:

📊 Metadata

🔗 References

📤 Share & Export

🔗 Related Vulnerabilities