CVE-2025-38208
📋 TL;DR
This CVE describes a NULL pointer dereference vulnerability in the Linux kernel's SMB client automount functionality. When tcon->origin_fullpath is set, the code fails to check if the 'page' variable is NULL before dereferencing it, which could cause a kernel panic. This affects Linux systems using SMB client functionality with automount configurations.
💻 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 leading to system crash and denial of service, potentially requiring physical or remote console access to reboot the system.
Likely Case
System crash or instability when specific SMB automount operations are performed, resulting in temporary denial of service until system reboot.
If Mitigated
No impact if the vulnerable code path is not triggered through SMB automount operations.
🎯 Exploit Status
Exploitation requires triggering specific SMB automount operations; no public exploits known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check kernel commits: 37166d63e42c34846a16001950ecec96229a8d17, a9e916fa5c7d0ec2256aa44aa24ddd92f529ce35, cce8e71ca1f7ad9045707f0d22490c1e9ed1df6c, f1e7a277a1736e12cc4bd6d93b8a5c439b8ca20c
Vendor Advisory: https://git.kernel.org/stable/c/37166d63e42c34846a16001950ecec96229a8d17
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version. 2. Check with your distribution vendor for specific kernel updates. 3. Reboot system after kernel update.
🔧 Temporary Workarounds
Disable SMB automount
linuxPrevent triggering of vulnerable code path by disabling SMB automount functionality
# Check automount configuration
# Review /etc/auto.master and related automount configs
# Disable SMB-specific automount entries
🧯 If You Can't Patch
- Restrict access to SMB shares and automount functionality to trusted users only
- Implement monitoring for kernel panic events and system crashes related to SMB operations
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with patched commits; examine if SMB automount is configured and activeCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes the fix commits; test SMB automount operations to ensure no crashes occur📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/messages or dmesg
- System crash logs related to SMB operations
- Automount failure logs
Network Indicators:
- SMB protocol traffic to automount shares
- Unusual SMB connection patterns
SIEM Query:
Search for 'kernel panic' OR 'Oops' OR 'NULL pointer dereference' in system logs combined with SMB-related events