CVE-2024-36931 – This CVE-2024-36931 is a Linux kernel vulnerabi... (How to Fix)

Q: What is the severity of CVE-2024-36931?

CVE-2024-36931 has a CVSS score of 7.1 (HIGH). This CVE-2024-36931 is a Linux kernel vulnerability in the s390/cio subsystem where a buffer copied from userspace is not properly NUL-terminated, allowing out-of-bounds reads when using scanf. This affects Linux systems running on IBM s390/zSeries architecture. Attackers could potentially read kernel memory, leading to information disclosure or system crashes.

📋 TL;DR

This CVE-2024-36931 is a Linux kernel vulnerability in the s390/cio subsystem where a buffer copied from userspace is not properly NUL-terminated, allowing out-of-bounds reads when using scanf. This affects Linux systems running on IBM s390/zSeries architecture. Attackers could potentially read kernel memory, leading to information disclosure or system crashes.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific affected versions not specified in CVE, but fix commits indicate multiple stable branches

Operating Systems: Linux distributions running on IBM s390/zSeries architecture

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems using s390 architecture; x86_64, ARM, and other architectures 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel memory disclosure leading to privilege escalation or system crash/DoS through kernel panic

🟠

Likely Case

Information disclosure of kernel memory contents, potentially exposing sensitive data

🟢

If Mitigated

Limited impact due to s390 architecture specificity and need for local access

🌐 Internet-Facing: LOW - Requires local access to the system

🏢 Internal Only: MEDIUM - Local users could exploit this on affected s390 systems

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access and knowledge of s390 architecture; exploit would need to trigger the vulnerable code path

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions with commits 06759ebaf75c19c87b2453a5e130e9e61e9b5d65 and related fixes

Vendor Advisory: https://git.kernel.org/stable/c/06759ebaf75c19c87b2453a5e130e9e61e9b5d65

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution vendor. 2. For s390-specific distributions, apply kernel patches from IBM or distribution maintainers. 3. Reboot system after kernel update.

🔧 Temporary Workarounds

Restrict local user access

linux

Limit access to s390 systems to trusted users only

Disable unnecessary s390/cio functionality

linux

If possible, disable or restrict the affected channel I/O subsystem

🧯 If You Can't Patch

Implement strict access controls to limit local user access to s390 systems
Monitor system logs for unusual activity or attempts to access s390/cio subsystem

🔍 How to Verify

Check if Vulnerable:

Check kernel version and architecture: uname -a (look for s390 in output) and verify if running unpatched kernel

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is updated and includes the fix commits, or check with distribution-specific security tools

📡 Detection & Monitoring

Log Indicators:

Kernel panic logs
OOB read errors in kernel logs
Unusual s390/cio subsystem activity

Network Indicators:

Not applicable - local vulnerability

SIEM Query:

Search for kernel panic events or s390-specific error messages in system logs

📊 Metadata

CVE ID: CVE-2024-36931

CVSS v3 Score: 7.1 (HIGH)

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

CWE: CWE-125

Published: May 30, 2024

Last Updated: January 15, 2025

🔗 References

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🔗 Related Vulnerabilities

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