CVE-2022-49765
📋 TL;DR
This CVE describes a race condition vulnerability in the Linux kernel's 9P network filesystem protocol implementation. The issue allows potential denial-of-service attacks or system instability due to improper locking mechanisms between interrupt and non-interrupt contexts. Systems using the 9P filesystem protocol (commonly in virtualization/container environments) are affected.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic or system crash leading to complete denial of service
Likely Case
System instability, application crashes, or service disruption affecting 9P filesystem operations
If Mitigated
Minimal impact if 9P protocol is not used or systems are properly patched
🎯 Exploit Status
Discovered via syzbot fuzzing; exploitation requires specific conditions and timing
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in kernel commits: 296ab4a813841ba1d5f40b03190fd1bd8f25aab0, 43bbadb7e4636dc02f6a283c2a39e6438e6173cd, 717b9b4f38703d7f5293059e3a242d16f76fa045
Vendor Advisory: https://git.kernel.org/stable/c/296ab4a813841ba1d5f40b03190fd1bd8f25aab0
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits
2. Reboot system to load new kernel
3. Verify 9P functionality if required
🔧 Temporary Workarounds
Disable 9P filesystem support
linuxRemove 9P protocol module if not required
rmmod 9p
rmmod 9pnet
echo 'blacklist 9p' >> /etc/modprobe.d/blacklist.conf
Avoid 9P usage in virtualization
linuxUse alternative filesystem sharing methods in virtualization/container environments
🧯 If You Can't Patch
- Disable 9P filesystem protocol in kernel configuration
- Monitor systems for instability/crashes related to filesystem operations
🔍 How to Verify
Check if Vulnerable:
Check if 9P module is loaded: lsmod | grep 9p
Check kernel version against patched versionsCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits and 9P operations work without lock warnings📡 Detection & Monitoring
Log Indicators:
- Kernel lockdep warnings
- System crashes during 9P operations
- dmesg warnings about inconsistent lock state
Network Indicators:
- 9P protocol traffic anomalies
SIEM Query:
source="kernel" AND ("inconsistent lock state" OR "9p" OR "trans_fd")