CVE-2024-27435 – A deadlock vulnerability in the Linux kernel's ... (How to Fix)

Q: What is the severity of CVE-2024-27435?

CVE-2024-27435 has a CVSS score of 5.5 (MEDIUM). A deadlock vulnerability in the Linux kernel's NVMe driver prevents reconnection of admin queues when using NVMe over RDMA. This causes permanent connection failures even when remote targets and networks are functional. Systems using NVMe over RDMA in production environments are primarily affected.

📋 TL;DR

A deadlock vulnerability in the Linux kernel's NVMe driver prevents reconnection of admin queues when using NVMe over RDMA. This causes permanent connection failures even when remote targets and networks are functional. Systems using NVMe over RDMA in production environments are primarily affected.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific affected kernel versions not specified in CVE, but patches available for multiple stable branches

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems using NVMe over RDMA (NVMe/RDMA) with admin queue reconnection scenarios.

📦 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

Permanent denial of service for NVMe storage access, requiring system reboot to restore functionality.

🟠

Likely Case

Intermittent or permanent NVMe storage connection failures during controller resets, disrupting storage operations.

🟢

If Mitigated

Minor performance impact during reconnection attempts with successful recovery after patch.

🌐 Internet-Facing: LOW - Requires local NVMe over RDMA configuration and specific trigger conditions.

🏢 Internal Only: MEDIUM - Affects production systems with NVMe over RDMA storage, causing availability issues.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: NO

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires specific NVMe over RDMA configuration and timing conditions during controller resets.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Multiple stable kernel versions with commit hashes provided in references

Vendor Advisory: https://git.kernel.org/stable/c/149afee5c7418ec5db9d7387b9c9a5c1eb7ea2a8

Restart Required: Yes

Instructions:

1. Identify current kernel version. 2. Apply appropriate kernel patch from provided git commits. 3. Rebuild kernel if using custom build. 4. Reboot system to load patched kernel.

🔧 Temporary Workarounds

Disable NVMe over RDMA

linux

Temporarily disable NVMe/RDMA functionality to avoid the deadlock scenario

modprobe -r nvme-rdma
echo 'blacklist nvme-rdma' > /etc/modprobe.d/disable-nvme-rdma.conf

Avoid controller resets

linux

Prevent conditions that trigger controller resets during normal operations

🧯 If You Can't Patch

Monitor NVMe connection status and implement automated recovery scripts for connection failures
Implement redundant storage paths or failover mechanisms to maintain availability during NVMe disruptions

🔍 How to Verify

Check if Vulnerable:

Check if system uses NVMe over RDMA: 'lsmod | grep nvme_rdma' and check kernel version against patched versions

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes one of the fix commits: 'uname -r' and check git log for commit hashes

📡 Detection & Monitoring

Log Indicators:

Kernel logs showing NVMe admin queue reconnection failures
dmesg entries about NVMe controller reset issues

Network Indicators:

RDMA connection establishment failures
NVMe admin command timeouts

SIEM Query:

source="kernel" AND "nvme" AND ("reconnect failed" OR "admin_q" OR "tag allocation")

📊 Metadata

CVE ID: CVE-2024-27435

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-667

Published: May 17, 2024

Last Updated: September 26, 2025

🔗 References

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🔗 Related Vulnerabilities

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