CVE-2025-38135
📋 TL;DR
A NULL pointer dereference vulnerability in the Linux kernel's serial driver could cause kernel panic or system crash when devm_ioremap() fails. This affects Linux systems using the affected serial driver. Attackers could potentially exploit this to cause denial of service.
💻 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 →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 access to restart affected systems.
Likely Case
System crash or kernel panic when the serial driver attempts to initialize with faulty hardware or under specific error conditions.
If Mitigated
System remains stable as the NULL check prevents dereferencing of invalid pointer.
🎯 Exploit Status
Exploitation requires triggering devm_ioremap() failure conditions, which may involve hardware manipulation or specific error states.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in Linux kernel stable branches (commits referenced in CVE)
Vendor Advisory: https://git.kernel.org/stable/c/19fd9f5a69363d33079097d866eb6082d61bf31d
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from distribution vendor. 2. Rebuild kernel if compiling from source with patches. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Disable mlb_usio driver
linuxPrevent loading of vulnerable driver module
echo 'blacklist mlb_usio' > /etc/modprobe.d/blacklist-mlb_usio.conf
rmmod mlb_usio
🧯 If You Can't Patch
- Ensure proper hardware configuration to prevent devm_ioremap() failures
- Implement system monitoring for kernel panics and have recovery procedures ready
🔍 How to Verify
Check if Vulnerable:
Check if mlb_usio driver is loaded: lsmod | grep mlb_usioCheck Version:
uname -rVerify Fix Applied:
Check kernel version after update and verify mlb_usio driver loads without issues📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/kern.log or dmesg
- NULL pointer dereference errors in kernel logs
Network Indicators:
- System becoming unresponsive to network requests
SIEM Query:
source="kernel" AND ("NULL pointer dereference" OR "kernel panic" OR "mlb_usio")🔗 References
- https://git.kernel.org/stable/c/19fd9f5a69363d33079097d866eb6082d61bf31d
- https://git.kernel.org/stable/c/548b0e81b9a0902a8bc8259430ed965663baadfc
- https://git.kernel.org/stable/c/81159a6b064142b993f2f39828b77e199c77872a
- https://git.kernel.org/stable/c/86bcae88c9209e334b2f8c252f4cc66beb261886
- https://git.kernel.org/stable/c/a05ebe384c7ca75476453f3070c67d9cf1d1a89f
- https://git.kernel.org/stable/c/a6c7c365734cd0fa1c5aa225a6294fdf80cad2ea
- https://git.kernel.org/stable/c/c23d87b43f7dba5eb12820f6cf21a1cd4f63eb3d
- https://git.kernel.org/stable/c/e1b144aebe6fb898d96ced8c990d7aa38fda4a7a
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
