CVE-2025-21746 Input: synaptics - fix crash when enabling pass-through port
A race condition in the Linux kernel Synaptics driver can cause a system crash when enabling a pass-through port.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-21746?
CVE-2025-21746 is a medium-severity vulnerability in Linux kernel, published on 27 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
Input: synaptics - fix crash when enabling pass-through port
When enabling a pass-through port an interrupt might come before psmouse driver binds to the pass-through port. However synaptics sub-driver tries to access psmouse instance presumably associated with the pass-through port to figure out if only 1 byte of response or entire protocol packet needs to be forwarded to the pass-through port and may crash if psmouse instance has not been attached to the port yet.
Fix the crash by introducing open() and close() methods for the port and check if the port is open before trying to access psmouse instance. Because psmouse calls serio_open() only after attaching psmouse instance to serio port instance this prevents the potential crash.
Weakness: CWE-367
Which versions are affected by CVE-2025-21746?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-21746?
Apply the vendor's patch.
Is CVE-2025-21746 being exploited?
There is no known exploitation of CVE-2025-21746 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-21746, DEBIAN-CVE-2025-21746, GHSA-9964-v64g-g4c3, ROOT-OS-UBUNTU-2404-CVE-2025-21746, UBUNTU-CVE-2025-21746.