CVE-2023-53245 – A NULL pointer dereference vulnerability in the... (How to Fix)

Q: What is the severity of CVE-2023-53245?

CVE-2023-53245 has a CVSS score of 5.5 (MEDIUM). A NULL pointer dereference vulnerability in the Linux kernel's storvsc driver causes kernel panics when handling virtual Fibre Channel timeouts in Hyper-V environments. This affects Linux systems running as guest VMs on Microsoft Hyper-V with virtual Fibre Channel storage. The vulnerability results in denial of service but does not allow privilege escalation or data compromise.

📋 TL;DR

A NULL pointer dereference vulnerability in the Linux kernel's storvsc driver causes kernel panics when handling virtual Fibre Channel timeouts in Hyper-V environments. This affects Linux systems running as guest VMs on Microsoft Hyper-V with virtual Fibre Channel storage. The vulnerability results in denial of service but does not allow privilege escalation or data compromise.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific kernel versions containing the vulnerable storvsc driver code (exact versions not specified in CVE, but patches available in stable kernel trees)

Operating Systems: Linux distributions running as guest VMs on Microsoft Hyper-V

Default Config Vulnerable: ✅ No

Notes: Only vulnerable when using Hyper-V virtual Fibre Channel (vFC) storage. Standard SCSI storage or other hypervisors are not affected.

📦 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 →

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 leading to system crash and denial of service, requiring host intervention to restart the VM.

🟠

Likely Case

System crash during transient storage timeouts, causing temporary service disruption until VM restart.

🟢

If Mitigated

With proper patching, timeout handling continues waiting instead of panicking, preventing crashes.

🌐 Internet-Facing: LOW - This vulnerability requires local access to the affected VM and specific Hyper-V storage configuration.

🏢 Internal Only: MEDIUM - Affects production VMs using Hyper-V virtual Fibre Channel storage, potentially causing service disruptions.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires triggering a timeout on virtual Fibre Channel I/O operations, which may occur naturally during storage issues or could potentially be induced through resource exhaustion attacks.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Patches available in stable kernel trees (commits: 048ebc9a28fb918ee635dd4b2fcf4248eb6e4050, 1678408d08f31a694d5150a56796dd04c9710b22, 175544ad48cbf56affeef2a679c6a4d4fb1e2881, 311db605e07f0d4fc0cc7ddb74f1e5692ea2f469, 763c06565055ae373fe7f89c11e1447bd1ded264)

Vendor Advisory: https://git.kernel.org/stable/c/048ebc9a28fb918ee635dd4b2fcf4248eb6e4050

Restart Required: Yes

Instructions:

1. Update to a patched kernel version from your distribution's repositories. 2. Reboot the system to load the new kernel. 3. Verify the fix by checking kernel version and monitoring for crashes during storage operations.

🔧 Temporary Workarounds

Disable virtual Fibre Channel

Hyper-V

Remove or disable virtual Fibre Channel storage devices from Hyper-V guest configuration

# Remove vFC devices from VM configuration in Hyper-V Manager or PowerShell

Use alternative storage

Hyper-V

Migrate from virtual Fibre Channel to standard SCSI or other supported storage types

# Convert storage or use different storage controllers in VM configuration

🧯 If You Can't Patch

Monitor systems for kernel panic events and have rapid recovery procedures in place
Implement storage redundancy and failover to minimize impact of potential crashes

🔍 How to Verify

Check if Vulnerable:

Check if system is a Hyper-V guest VM with virtual Fibre Channel storage and running an unpatched kernel version containing the vulnerable storvsc driver code.

Check Version:

uname -r

Verify Fix Applied:

After patching, verify the kernel version includes the fix commits and monitor for absence of kernel panics during storage operations.

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages in /var/log/messages or dmesg output
Storage timeout errors followed by system crashes

Network Indicators:

Sudden loss of connectivity to VM after storage operations

SIEM Query:

search 'kernel panic' OR 'NULL pointer dereference' AND 'storvsc' OR 'fc_eh_timed_out'

📊 Metadata

CVE ID: CVE-2023-53245

CVSS v3 Score: 5.5 (MEDIUM)

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

CWE: CWE-476

EPSS Score: 0.01% exploit probability (2.3th percentile)

Published: September 15, 2025

Last Updated: January 14, 2026

🔗 References

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