CVE-2025-37776
📋 TL;DR
This CVE describes a use-after-free vulnerability in the Linux kernel's ksmbd (SMB server) module. Attackers could potentially exploit this race condition to crash the kernel or execute arbitrary code. Systems running affected Linux kernel versions with ksmbd enabled are vulnerable.
💻 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 →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
Kernel panic causing system instability or denial of service, requiring system reboot.
If Mitigated
Limited impact if ksmbd is disabled or proper access controls restrict SMB connections.
🎯 Exploit Status
Exploitation requires race condition timing and SMB access. No public exploits known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check kernel commit references for specific patched versions
Vendor Advisory: https://git.kernel.org/stable/c/18b4fac5ef17f77fed9417d22210ceafd6525fc7
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 is updated.
🔧 Temporary Workarounds
Disable ksmbd module
linuxPrevent loading of vulnerable ksmbd kernel module
echo 'blacklist ksmbd' >> /etc/modprobe.d/blacklist-ksmbd.conf
rmmod ksmbd
Restrict SMB access
linuxUse firewall rules to limit SMB connections to trusted networks
iptables -A INPUT -p tcp --dport 445 -s TRUSTED_NETWORK -j ACCEPT
iptables -A INPUT -p tcp --dport 445 -j DROP
🧯 If You Can't Patch
- Disable ksmbd module if not required for business operations
- Implement strict network segmentation to isolate SMB servers from untrusted networks
🔍 How to Verify
Check if Vulnerable:
Check if ksmbd module is loaded: lsmod | grep ksmbd. If loaded, check kernel version against patched versions.Check Version:
uname -rVerify Fix Applied:
Verify kernel version is updated and ksmbd module version matches patched kernel. Check dmesg for any ksmbd-related errors.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/messages or dmesg
- ksmbd crash logs
- Unexpected system reboots
Network Indicators:
- Unusual SMB connection patterns to port 445
- Multiple SMB session establishment attempts
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "ksmbd")