CVE-2025-21927
📋 TL;DR
A memory corruption vulnerability in the Linux kernel's NVMe over TCP implementation allows attackers to cause memory corruption by sending specially crafted packets with invalid header lengths. This affects systems using NVMe over TCP with header digests enabled. Attackers could potentially crash the system or execute arbitrary code.
💻 Affected Systems
- Linux kernel
📦 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 →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
Remote code execution leading to complete system compromise, data theft, or persistent backdoor installation.
Likely Case
Kernel panic or system crash causing denial of service and potential data loss.
If Mitigated
System remains stable with proper packet validation and boundary checks in place.
🎯 Exploit Status
Exploitation requires network access to NVMe over TCP services and header digests to be enabled. No public exploits known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 22b06c89aa6b2d1ecb8aea72edfb9d53af8d5126, 9fbc953d6b38bc824392e01850f0aeee3b348722, ad95bab0cd28ed77c2c0d0b6e76e03e031391064
Vendor Advisory: https://git.kernel.org/stable/c/22b06c89aa6b2d1ecb8aea72edfb9d53af8d5126
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution's repositories. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable NVMe over TCP header digests
linuxDisable header digest feature in NVMe over TCP configuration to prevent exploitation
# Check current NVMe configuration
# Modify /etc/nvme/nvme.conf to disable header digests
# Restart nvme-tcp services
Network segmentation
linuxRestrict network access to NVMe over TCP services to trusted hosts only
# Use firewall rules to restrict access
iptables -A INPUT -p tcp --dport 4420 -s trusted_host -j ACCEPT
iptables -A INPUT -p tcp --dport 4420 -j DROP
🧯 If You Can't Patch
- Disable NVMe over TCP completely if not required
- Implement strict network access controls to limit exposure to NVMe over TCP services
🔍 How to Verify
Check if Vulnerable:
Check kernel version and verify if NVMe over TCP with header digests is enabled. Use: uname -r and check NVMe configuration files.Check Version:
uname -rVerify Fix Applied:
Verify kernel version is updated to patched version and test NVMe over TCP functionality remains operational.📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- NVMe error messages about invalid headers
- System crash/reboot events
Network Indicators:
- Unusual traffic to NVMe over TCP port (typically 4420)
- Packets with abnormal header lengths
SIEM Query:
source="kernel" AND ("panic" OR "oops") OR source="nvme" AND ("invalid header" OR "corruption")