CVE-2025-21695: platform/x86: dell-uart-backlight: fix serdev race
In the Linux kernel, the following vulnerability has been resolved:
platform/x86: dell-uart-backlight: fix serdev race
The delluartblserdevprobe() function calls devmserdevdeviceopen() before setting the client ops via serdevdevicesetclientops(). This ordering can trigger a NULL pointer dereference in the serdev controller's receivebuf handler, as it assumes serdev->ops is valid when SERPORTACTIVE is set.
This is similar to the issue fixed in commit 5e700b384ec1 ("platform/chrome: crosecuart: properly fix race condition") where devmserdevdeviceopen() was called before fully initializing the device.
Fix the race by ensuring client ops are set before enabling the port via devmserdevdeviceopen().
Note, serdevdevicesetbaudrate() and serdevdevicesetflowcontrol() calls should be after the devmserdevdeviceopen() call.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2025-21695?
The severity of CVE-2025-21695 has not been explicitly classified but pertains to a race condition in the Linux kernel.
How do I fix CVE-2025-21695?
To fix CVE-2025-21695, apply the latest patches from the Linux kernel that address this specific vulnerability.
What are the affected systems for CVE-2025-21695?
CVE-2025-21695 affects systems running vulnerable versions of the Linux kernel related to the dell_uart_bl_serdev_probe() function.
What type of vulnerability is CVE-2025-21695?
CVE-2025-21695 is a race condition vulnerability found in the Linux kernel's handling of device operations.
Is CVE-2025-21695 being actively exploited?
As of now, there is no public indication that CVE-2025-21695 is being actively exploited in the wild.