CVE-2025-21685
📋 TL;DR
A race condition in the Linux kernel's Lenovo Yoga Tab 2 Pro 1380 fast charger driver can cause a NULL pointer dereference when the serial device port is enabled before client operations are properly initialized. This affects Linux systems using this specific driver, potentially causing kernel panics or system crashes. The vulnerability requires local access to trigger.
💻 Affected Systems
- Linux kernel with lenovo-yoga-tab2-pro-1380-fastcharger driver
📦 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 →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, requiring physical or remote reboot.
Likely Case
System crash or kernel panic when the specific driver is loaded and the race condition is triggered during device initialization.
If Mitigated
No impact if the vulnerable driver is not loaded or the system has been patched.
🎯 Exploit Status
Requires local access and timing to trigger the race condition. Not a remote code execution vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel with commits 3f67e07873df3c6d9ce2582260b83732e1d3a40b or 59616a91e5e74833b2008b56c66879857c616006
Vendor Advisory: https://git.kernel.org/stable/c/3f67e07873df3c6d9ce2582260b83732e1d3a40b
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. Rebuild kernel if compiling from source. 3. Reboot system to load patched kernel.
🔧 Temporary Workarounds
Disable vulnerable driver
linuxPrevent loading of the lenovo-yoga-tab2-pro-1380-fastcharger kernel module
echo 'blacklist lenovo-yoga-tab2-pro-1380-fastcharger' > /etc/modprobe.d/blacklist-lenovo-yoga-tab2.conf
update-initramfs -u
reboot
🧯 If You Can't Patch
- Avoid using Lenovo Yoga Tab 2 Pro 1380 devices with affected systems
- Implement strict access controls to prevent local users from triggering driver initialization
🔍 How to Verify
Check if Vulnerable:
Check if the driver is loaded: lsmod | grep lenovo-yoga-tab2-pro-1380-fastchargerCheck Version:
uname -rVerify Fix Applied:
Check kernel version contains fix commits: grep -q '3f67e07873df3c6d9ce2582260b83732e1d3a40b\|59616a91e5e74833b2008b56c66879857c616006' /proc/version📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/kern.log or dmesg
- NULL pointer dereference errors mentioning serdev or lenovo-yoga-tab2
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("NULL pointer dereference" OR "kernel panic" OR "lenovo-yoga-tab2")