CVE-2023-53462 – This CVE describes an uninitialized value acces... (How to Fix)

Q: What is the severity of CVE-2023-53462?

CVE-2023-53462 has a CVSS score of 5.5 (MEDIUM). This CVE describes an uninitialized value access vulnerability in the Linux kernel's HSR (High-availability Seamless Redundancy) protocol implementation. When processing VLAN-tagged packets, the fill_frame_info() function can read uninitialized memory, potentially leading to kernel memory corruption. Systems using HSR networking with affected kernel versions are vulnerable.

📋 TL;DR

This CVE describes an uninitialized value access vulnerability in the Linux kernel's HSR (High-availability Seamless Redundancy) protocol implementation. When processing VLAN-tagged packets, the fill_frame_info() function can read uninitialized memory, potentially leading to kernel memory corruption. Systems using HSR networking with affected kernel versions are vulnerable.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific affected versions not explicitly stated in CVE, but patches exist for multiple stable branches (see references).

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ✅ No

Notes: Only affects systems with HSR protocol enabled (CONFIG_HSR). HSR is not enabled by default in most distributions.

📦 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel memory corruption leading to system crash, denial of service, or potential privilege escalation if combined with other vulnerabilities.

🟠

Likely Case

System instability, kernel panics, or denial of service affecting HSR network functionality.

🟢

If Mitigated

Limited impact if HSR protocol is not used or VLAN traffic is filtered.

🌐 Internet-Facing: LOW - HSR is typically used in industrial/embedded networks, not internet-facing systems.

🏢 Internal Only: MEDIUM - Affects internal industrial/SCADA networks using HSR for redundancy.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires sending specially crafted VLAN packets to HSR interfaces. Found via syzbot fuzzing.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Multiple stable kernel versions with fixes (see reference commits)

Vendor Advisory: https://git.kernel.org/stable/c/1e90a93ac4845c31724ec5dc96fb51e608435a9d

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version. 2. Check distribution security advisories. 3. Reboot system after kernel update.

🔧 Temporary Workarounds

Disable HSR protocol

linux

Remove HSR kernel module if not needed

rmmod hsr
echo 'blacklist hsr' >> /etc/modprobe.d/blacklist.conf

Block VLAN traffic to HSR interfaces

linux

Use firewall rules to block VLAN-tagged packets

iptables -A INPUT -m vlan --vlan-id 1-4094 -j DROP
iptables -A FORWARD -m vlan --vlan-id 1-4094 -j DROP

🧯 If You Can't Patch

Ensure HSR protocol is disabled if not required
Implement network segmentation to isolate HSR networks from VLAN traffic sources

🔍 How to Verify

Check if Vulnerable:

Check if HSR module is loaded: lsmod | grep hsr. Check kernel version against patched versions.

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is updated and HSR module loads without errors in dmesg.

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
HSR protocol errors in dmesg
KMSAN uninit-value warnings

Network Indicators:

VLAN-tagged packets sent to HSR interfaces
Unusual HSR protocol traffic patterns

SIEM Query:

source="kernel" AND ("KMSAN" OR "uninit-value" OR "hsr_forward")

📊 Metadata

CVE ID: CVE-2023-53462

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-908

EPSS Score: 0.02% exploit probability (5.5th percentile)

Published: October 1, 2025

Last Updated: January 16, 2026

🔗 References

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🔗 Related Vulnerabilities

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