CVE-2025-22043
📋 TL;DR
This CVE addresses a missing bounds check in the Linux kernel's ksmbd (SMB server) durable handle context handling. An attacker could potentially exploit this to cause kernel memory corruption, leading to system crashes or privilege escalation. Systems running vulnerable Linux kernel versions with ksmbd enabled 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 →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 memory corruption leading to system crash (denial of service) or potential privilege escalation to root.
Likely Case
System crash or kernel panic causing denial of service.
If Mitigated
No impact if ksmbd is disabled or proper access controls restrict SMB access.
🎯 Exploit Status
Exploitation requires SMB access to the vulnerable system. No public exploit code is currently available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing the fix commits (1107b9ed92194603593c51829a3887812ae9e806 and related)
Vendor Advisory: https://git.kernel.org/stable/c/1107b9ed92194603593c51829a3887812ae9e806
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution. 2. Reboot system to load new kernel. 3. Verify ksmbd module is using patched code.
🔧 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 network access
linuxUse firewall rules to limit access to ksmbd service
iptables -A INPUT -p tcp --dport 445 -j DROP
iptables -A INPUT -p tcp --dport 139 -j DROP
🧯 If You Can't Patch
- Disable ksmbd module if not required for operations
- Implement strict network segmentation and firewall rules to limit SMB access to trusted sources only
🔍 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 shows correct version in modinfo output.📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- ksmbd crash messages in dmesg or system logs
- Unexpected SMB connection attempts
Network Indicators:
- Unusual SMB traffic patterns to port 445/139
- Multiple failed SMB connections from single source
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "ksmbd")🔗 References
- https://git.kernel.org/stable/c/1107b9ed92194603593c51829a3887812ae9e806
- https://git.kernel.org/stable/c/29b946714d6aa77de54c71243bba39469ac43ef2
- https://git.kernel.org/stable/c/542027e123fc0bfd61dd59e21ae0ee4ef2101b29
- https://git.kernel.org/stable/c/8d4848c45943c9cf5e86142fd7347efa97f497db
- https://git.kernel.org/stable/c/f0db3d9d416e332a0d6f045a1509539d3a4cd898
