CVE-2023-53494 – This CVE describes a use-after-free vulnerabili... (How to Fix)

Q: What is the severity of CVE-2023-53494?

CVE-2023-53494 has a CVSS score of 7.8 (HIGH). This CVE describes a use-after-free vulnerability in the Linux kernel's XTS (XEX-based tweaked-codebook mode with ciphertext stealing) cryptographic module. When the kernel handles backlogged encryption/decryption requests with MAY_BACKLOG flag, it fails to properly handle EBUSY return codes, leading to premature freeing of request data structures. This affects all Linux systems using the XTS encryption module.

📋 TL;DR

This CVE describes a use-after-free vulnerability in the Linux kernel's XTS (XEX-based tweaked-codebook mode with ciphertext stealing) cryptographic module. When the kernel handles backlogged encryption/decryption requests with MAY_BACKLOG flag, it fails to properly handle EBUSY return codes, leading to premature freeing of request data structures. This affects all Linux systems using the XTS encryption module.

💻 Affected Systems

Products:

Linux kernel

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

Operating Systems: All Linux distributions

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems using the XTS cryptographic module. Many distributions use XTS for disk encryption (LUKS/dm-crypt) and filesystem encryption.

📦 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel panic, system crash, or potential privilege escalation leading to full system compromise if an attacker can trigger the use-after-free condition to execute arbitrary code in kernel context.

🟠

Likely Case

System instability, kernel crashes, or denial of service affecting cryptographic operations and dependent services.

🟢

If Mitigated

Limited impact if systems are patched or don't use XTS encryption with backlogged requests.

🌐 Internet-Facing: MEDIUM - Requires local access or ability to trigger specific cryptographic operations, but could be chained with other vulnerabilities.

🏢 Internal Only: MEDIUM - Same as internet facing, but requires initial access to the system.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: HIGH - Requires specific conditions to trigger the EBUSY/backlog scenario and control timing for use-after-free exploitation.

Exploitation requires local access and ability to perform cryptographic operations. No public exploits known at this time.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Fixed in kernel commits: 51c082514c2dedf2711c99d93c196cc4eedceb40, 57c3e1d63b63dc0841d41df729297cd7c1c35808, 912eb10b65646ffd222256c78a1c566a3dac177d, 92a07ba4f0af2cccdc2aa5ee32679c9c9714db90, d5870848879291700fe6c5257dcb48aadd10425c

Vendor Advisory: https://git.kernel.org/stable/c/51c082514c2dedf2711c99d93c196cc4eedceb40

Restart Required: Yes

Instructions:

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

🔧 Temporary Workarounds

Disable XTS module

linux

Blacklist or disable the XTS cryptographic module if not required

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

Avoid MAY_BACKLOG flag

linux

Modify applications to avoid using MAY_BACKLOG flag with XTS operations

🧯 If You Can't Patch

Restrict access to cryptographic operations to trusted users only
Monitor system logs for kernel panics or crashes related to cryptographic operations

🔍 How to Verify

Check if Vulnerable:

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

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is patched and check git commit history contains the fix commits

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
Oops messages in /var/log/kern.log or dmesg
Cryptographic operation failures

SIEM Query:

source="kernel" AND ("panic" OR "Oops" OR "use-after-free") AND ("crypto" OR "XTS")

📊 Metadata

CVE ID: CVE-2023-53494

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-416

EPSS Score: 0.02% exploit probability (5.6th percentile)

Published: October 1, 2025

Last Updated: January 16, 2026

🔗 References

📤 Share & Export

📄 Export Markdown 📋 Export JSON

🔗 Related Vulnerabilities

If you're affected by CVE-2023-53494, you might also want to check these: