CVE-2023-53616 – This is a double-free vulnerability in the Linu... (How to Fix)

Q: What is the severity of CVE-2023-53616?

CVE-2023-53616 has a CVSS score of 7.8 (HIGH). This is a double-free vulnerability in the Linux kernel's JFS filesystem implementation. When unmounting a JFS filesystem, the kernel can attempt to free the same memory twice, potentially leading to system crashes or kernel memory corruption. This affects any Linux system using the JFS filesystem.

📋 TL;DR

This is a double-free vulnerability in the Linux kernel's JFS filesystem implementation. When unmounting a JFS filesystem, the kernel can attempt to free the same memory twice, potentially leading to system crashes or kernel memory corruption. This affects any Linux system using the JFS filesystem.

💻 Affected Systems

Products:

Linux kernel

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

Operating Systems: Linux distributions with vulnerable kernel versions

Default Config Vulnerable: ✅ No

Notes: Only affects systems using JFS filesystem. Most systems use ext4 or other filesystems by default.

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel panic leading to system crash, potential privilege escalation if memory corruption can be controlled, or denial of service.

🟠

Likely Case

System crash or kernel panic when unmounting JFS filesystems, particularly during remount operations that fail.

🟢

If Mitigated

System remains stable as the double-free is prevented by proper memory management.

🌐 Internet-Facing: LOW - Requires local filesystem access and JFS usage, not directly exploitable over network.

🏢 Internal Only: MEDIUM - Local users with JFS filesystem access could potentially trigger crashes affecting system stability.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access and ability to mount/unmount JFS filesystems. Found by syzbot fuzzer.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Linux kernel with commits 114ea3cb13ab25f7178cb60283adb93d2f96dad7 or later

Vendor Advisory: https://git.kernel.org/stable/c/114ea3cb13ab25f7178cb60283adb93d2f96dad7

Restart Required: Yes

Instructions:

1. Update Linux kernel to version containing the fix. 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 'install jfs /bin/false' >> /etc/modprobe.d/disable-jfs.conf
rmmod jfs 2>/dev/null || true

Avoid JFS usage

linux

Do not mount or use JFS filesystems

# Check for JFS mounts: mount | grep -i jfs
# Unmount any JFS filesystems if found

🧯 If You Can't Patch

Restrict mount permissions to prevent unauthorized users from mounting JFS filesystems
Monitor system logs for JFS-related errors or crashes and implement failover/redundancy

🔍 How to Verify

Check if Vulnerable:

Check kernel version and if JFS module is loaded: uname -r && lsmod | grep jfs

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes fix commit or is from distribution with security update applied

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
KASAN reports of double-free
JFS unmount errors in system logs

Network Indicators:

None - local vulnerability only

SIEM Query:

source="kernel" AND ("double-free" OR "KASAN" OR "jfs" OR "diUnmount")

📊 Metadata

CVE ID: CVE-2023-53616

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-415

Published: October 4, 2025

Last Updated: February 5, 2026

🤖 AI-assisted analysis, reviewed for accuracy

🔗 References

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🔗 Related Vulnerabilities

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