CVE-2025-38146
📋 TL;DR
A vulnerability in the Linux kernel's Open vSwitch module allows specially crafted MPLS packets to cause a dead loop during parsing, leading to CPU soft lockups and denial of service. This affects systems running Linux kernels with Open vSwitch enabled, particularly network virtualization environments and cloud infrastructure. Attackers can exploit this to disrupt network functionality and cause system instability.
💻 Affected Systems
- Linux kernel with Open vSwitch 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 →⚠️ Risk & Real-World Impact
Worst Case
Complete system unavailability due to CPU soft lockup, causing network disruption and potential cascading failures in virtualized environments.
Likely Case
Denial of service affecting network connectivity and performance in systems processing MPLS traffic through Open vSwitch.
If Mitigated
Minimal impact if Open vSwitch is not used or MPLS traffic is filtered at network boundaries.
🎯 Exploit Status
Exploitation requires network access to send MPLS packets to systems with Open vSwitch enabled. No authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patched in kernel commits referenced in CVE (e.g., 0bdc924bfb319fb10d1113cbf091fc26fb7b1f99)
Vendor Advisory: https://git.kernel.org/stable/c/0bdc924bfb319fb10d1113cbf091fc26fb7b1f99
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution vendor. 2. Reboot system to load new kernel. 3. Verify Open vSwitch module loads correctly after reboot.
🔧 Temporary Workarounds
Disable Open vSwitch module
linuxUnload Open vSwitch kernel module if not required
sudo rmmod openvswitch
Block MPLS traffic at network boundary
linuxFilter MPLS packets using firewall rules
sudo iptables -A INPUT -p mpls -j DROP
sudo iptables -A FORWARD -p mpls -j DROP
🧯 If You Can't Patch
- Implement network segmentation to isolate systems using Open vSwitch
- Deploy network monitoring to detect and alert on MPLS traffic anomalies
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if Open vSwitch module is loaded: uname -r && lsmod | grep openvswitchCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is newer than vulnerable versions and test with MPLS traffic📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- Soft lockup CPU stall warnings
- Open vSwitch error logs
Network Indicators:
- Unusual MPLS packet patterns
- Network connectivity loss to Open vSwitch systems
SIEM Query:
source="kernel" AND ("soft lockup" OR "CPU stuck" OR "array-index-out-of-bounds")🔗 References
- https://git.kernel.org/stable/c/0bdc924bfb319fb10d1113cbf091fc26fb7b1f99
- https://git.kernel.org/stable/c/3c1906a3d50cb94fd0a10e97a1c0a40c0f033cb7
- https://git.kernel.org/stable/c/4b9a086eedc1fddae632310386098c12155e3d0a
- https://git.kernel.org/stable/c/69541e58323ec3e3904e1fa87a6213961b1f52f4
- https://git.kernel.org/stable/c/8ebcd311b4866ab911d1445ead08690e67f0c488
- https://git.kernel.org/stable/c/ad17eb86d042d72a59fd184ad1adf34f5eb36843
- https://git.kernel.org/stable/c/f26fe7c3002516dd3c288f1012786df31f4d89e0
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
