CVE-2022-50476
📋 TL;DR
A memory management vulnerability in the Linux kernel's NTB (Non-Transparent Bridge) network driver where skb (socket buffer) cleanup functions use interrupt-unsafe methods in interrupt context. This causes kernel warnings and severe performance degradation on AMD systems with PTDMA DMA engines. Systems using NTB networking with affected kernel versions are vulnerable.
💻 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 →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 or system crash due to improper memory handling in interrupt context, leading to denial of service.
Likely Case
Kernel warning messages in system logs and significant network performance degradation (up to 10x slower) on affected AMD systems.
If Mitigated
Minor performance impact or no noticeable effect on Intel systems using IOAT DMA with tasklets.
🎯 Exploit Status
Exploitation occurs naturally during NTB network traffic on vulnerable AMD systems, not requiring malicious payloads.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patched in stable kernel commits: 07e28a8f4502, 13286ad1c7c4, 14d245da57a1, 21296a52caa6, 5f7d78b2b12a
Vendor Advisory: https://git.kernel.org/stable/c/07e28a8f450217db679802ebd4de0915556ce846
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version. 2. Check distribution-specific security advisories. 3. Reboot system after kernel update.
🔧 Temporary Workarounds
Disable NTB networking
linuxRemove or disable ntb_netdev module if not required
rmmod ntb_netdev
echo 'blacklist ntb_netdev' >> /etc/modprobe.d/blacklist.conf
Use Intel IOAT DMA systems
linuxDeploy on Intel systems where impact is less severe
🧯 If You Can't Patch
- Monitor system logs for kernel warnings from skb_release_head_state()
- Avoid heavy NTB network traffic on AMD PTDMA systems
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if NTB networking is active: lsmod | grep ntb_netdevCheck Version:
uname -rVerify Fix Applied:
Verify kernel is updated beyond patch commits and no warnings in dmesg about skb_release_head_state📡 Detection & Monitoring
Log Indicators:
- Kernel warnings: 'WARNING: CPU: ... at net/core/skbuff.c:... skb_release_head_state()' in dmesg or /var/log/kern.log
Network Indicators:
- Unusually low TCP/IP performance (~2 Gb/s instead of expected 20 Gb/s) on NTB interfaces
SIEM Query:
source="kernel" AND "skb_release_head_state" AND "WARNING"🔗 References
- https://git.kernel.org/stable/c/07e28a8f450217db679802ebd4de0915556ce846
- https://git.kernel.org/stable/c/13286ad1c7c49c606fdcba4cf66f953a1a16c1ca
- https://git.kernel.org/stable/c/14d245da57a11e80277ab455aa9b6dcc5ed38a19
- https://git.kernel.org/stable/c/21296a52caa6a6bad6debdfe40ad81d4f1a27e69
- https://git.kernel.org/stable/c/5f7d78b2b12a9d561f48fa00bab29b40f4616dad
- https://git.kernel.org/stable/c/8b78493968ed3cef0326183ed059c55e42f24d5b
- https://git.kernel.org/stable/c/a6b9e09403102bdf8402dae734800e4916c7ea58
- https://git.kernel.org/stable/c/d4460c82177899751975180c268f352893302221
- https://git.kernel.org/stable/c/dd860b39aa7c7b82e6c99b6fdb99d4610ce49d67
