CVE-2022-49654
📋 TL;DR
A vulnerability in the Linux kernel's Qualcomm Atheros QCA8K Ethernet switch driver causes network disruption when changing MTU settings. If exploited, it makes the management interface unreachable by causing the switch to stop processing packets. This affects systems using the qca8k driver for network switching.
💻 Affected Systems
- Linux kernel with qca8k driver
📦 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
Network switch becomes unresponsive, requiring physical reset to restore connectivity, causing extended network downtime.
Likely Case
Accidental MTU change triggers the bug, making the management interface unreachable until system reboot or switch reset.
If Mitigated
Limited to local privilege escalation required to modify MTU settings, with network disruption contained to affected switch.
🎯 Exploit Status
Exploitation requires local access and ability to modify network interface MTU settings.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel stable releases containing commits 188c798f3c25, 1993f5a06736, or 386228c694bf
Vendor Advisory: https://git.kernel.org/stable/c/188c798f3c2554fa0d7147e9b97baf144b817019
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version. 2. Reboot system to load new kernel. 3. Verify driver functionality post-update.
🔧 Temporary Workarounds
Avoid MTU changes
linuxPrevent modification of MTU settings on interfaces using qca8k driver
# Restrict MTU modification permissions
chmod 644 /sys/class/net/*/mtu
# Or use capability restrictions
🧯 If You Can't Patch
- Restrict user permissions to prevent MTU modification on affected interfaces
- Implement monitoring for MTU change attempts on qca8k interfaces
🔍 How to Verify
Check if Vulnerable:
Check if system uses qca8k driver: lsmod | grep qca8k && check kernel version against patched releasesCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits and test MTU change on qca8k interface without disruption📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages related to qca8k driver
- Network interface going down after MTU change
- Switch management becoming unreachable
Network Indicators:
- Sudden loss of connectivity on switch management interface
- ARP/MAC address table stops updating
SIEM Query:
source="kernel" AND "qca8k" AND ("panic" OR "BUG")