CVE-2026-23226
📋 TL;DR
A race condition vulnerability in the Linux kernel's ksmbd (SMB server) component allows use-after-free attacks in multi-channel SMB sessions. This affects systems running vulnerable Linux kernel versions with ksmbd enabled. Attackers could potentially crash the kernel or execute arbitrary code.
💻 Affected Systems
- Linux kernel with ksmbd module
📦 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 leading to system crash or potential arbitrary code execution with kernel privileges, resulting in complete system compromise.
Likely Case
System instability, kernel crashes, or denial of service affecting SMB file sharing services.
If Mitigated
Limited to denial of service if exploit attempts fail or are detected by security controls.
🎯 Exploit Status
Exploitation requires race condition timing and multi-channel SMB session access. No public exploits known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel with commits 36ef605c0395b94b826a8c8d6f2697071173de6e and e4a8a96a93d08570e0405cfd989a8a07e5b6ff33 applied
Vendor Advisory: https://git.kernel.org/stable/c/36ef605c0395b94b826a8c8d6f2697071173de6e
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution vendor. 2. Reboot system to load new kernel. 3. Verify ksmbd module loads correctly if needed.
🔧 Temporary Workarounds
Disable ksmbd module
linuxUnload ksmbd kernel module if not required for SMB file sharing
sudo rmmod ksmbd
echo 'blacklist ksmbd' | sudo tee /etc/modprobe.d/ksmbd-blacklist.conf
Disable SMB multi-channel
linuxConfigure ksmbd to disable multi-channel sessions
Add 'smb2 max_channels=1' to ksmbd configuration
🧯 If You Can't Patch
- Disable ksmbd module entirely if SMB file sharing is not required
- Restrict network access to SMB services using firewall rules (iptables/nftables)
🔍 How to Verify
Check if Vulnerable:
Check if ksmbd module is loaded: lsmod | grep ksmbd. Check kernel version against patched commits.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes the fix commits: grep -q '36ef605c0395b94b826a8c8d6f2697071173de6e\|e4a8a96a93d08570e0405cfd989a8a07e5b6ff33' /proc/version_signature📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- ksmbd crash logs in dmesg or journalctl
- Unexpected SMB session terminations
Network Indicators:
- Multiple SMB channel establishment attempts in short timeframes
- Abnormal SMB protocol traffic patterns
SIEM Query:
source="kernel" AND ("panic" OR "Oops") AND "ksmbd" OR source="ksmbd" AND "crash"