CVE-2025-38092
📋 TL;DR
This CVE addresses a NULL pointer dereference vulnerability in the Linux kernel's ksmbd module, which handles SMB file sharing. If exploited, it could cause kernel panics or system crashes on systems using ksmbd. This affects Linux systems with ksmbd enabled, particularly those configured as SMB servers.
💻 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 →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 leading to system crash and denial of service, potentially requiring physical intervention to reboot the system.
Likely Case
System crash or kernel panic causing temporary denial of service until system reboot.
If Mitigated
No impact if ksmbd is not enabled or if the system is patched.
🎯 Exploit Status
Exploitation requires access to trigger the vulnerable code path in ksmbd, which typically requires SMB client access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel versions with the fix commits referenced in the CVE
Vendor Advisory: https://git.kernel.org/stable/c/10379171f346e6f61d30d9949500a8de4336444a
Restart Required: Yes
Instructions:
1. Update Linux kernel to a version containing the fix commits. 2. Reboot the system. 3. Verify ksmbd module loads correctly.
🔧 Temporary Workarounds
Disable ksmbd module
linuxUnload the ksmbd kernel module to prevent exploitation
sudo rmmod ksmbd
echo 'blacklist ksmbd' | sudo tee /etc/modprobe.d/ksmbd-blacklist.conf
Restrict SMB access
linuxLimit network access to ksmbd service using firewall rules
sudo iptables -A INPUT -p tcp --dport 445 -j DROP
sudo iptables -A INPUT -p tcp --dport 139 -j DROP
🧯 If You Can't Patch
- Disable ksmbd module if not required for business operations
- Implement strict network segmentation to isolate systems using ksmbd
🔍 How to Verify
Check if Vulnerable:
Check if ksmbd module is loaded: lsmod | grep ksmbd. If loaded and kernel version is vulnerable, system is at risk.Check Version:
uname -rVerify Fix Applied:
Check kernel version is patched and ksmbd module loads without errors after reboot.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/kern.log or dmesg
- ksmbd service crashes or restarts
Network Indicators:
- Unexpected SMB connection attempts to ksmbd ports
- Multiple failed SMB requests followed by service unavailability
SIEM Query:
source="kernel" AND "panic" OR "Oops" AND "ksmbd"