CVE-2022-50335
📋 TL;DR
This CVE-2022-50335 is a use-after-free vulnerability in the Linux kernel's 9p filesystem client. It allows attackers to cause kernel memory corruption by exploiting uninitialized request structures, potentially leading to system crashes or privilege escalation. Systems using the 9p filesystem client 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 →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, system crash, or potential privilege escalation leading to full system compromise.
Likely Case
System instability, kernel crashes, or denial of service conditions.
If Mitigated
Limited impact if 9p filesystem is not in use or properly isolated.
🎯 Exploit Status
Exploitation requires local access and specific timing conditions. The syzbot report shows it can be triggered through xattr operations.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 1cabce56626a61f4f02452cba61ad4332a4b73f8, 26273ade77f54716e30dfd40ac6e85ceb54ac0f9, 73c47b3123b351de2d3714a72a336c0f72f203af, or 967fc34f297e40fd2e068cf6b0c3eb4916228539
Vendor Advisory: https://git.kernel.org/stable/c/1cabce56626a61f4f02452cba61ad4332a4b73f8
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable 9p filesystem
LinuxRemove or disable 9p filesystem support if not needed
modprobe -r 9p
echo 'blacklist 9p' >> /etc/modprobe.d/blacklist.conf
🧯 If You Can't Patch
- Disable 9p filesystem module if not required
- Restrict access to users who can mount 9p filesystems
🔍 How to Verify
Check if Vulnerable:
Check if 9p module is loaded: lsmod | grep 9p AND check kernel version against patched versionsCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes one of the fix commits AND test 9p functionality remains working📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- Oops messages mentioning p9_client_walk or p9_req_put
- Corrupted memory warnings in dmesg
Network Indicators:
- Unusual 9p network traffic patterns
SIEM Query:
source="kernel" AND ("p9_client_walk" OR "p9_req_put" OR "use-after-free" OR "kernel panic")