CVE-2025-68312: usbnet: Prevents free active kevent

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-12-16 · updated 2026-10-14

Description

In the Linux kernel, the following vulnerability has been resolved: usbnet: Prevents free active kevent The root cause of this issue are: 1. When probing the usbnet device, executing usbnet_link_change(dev, 0, 0); put the kevent work in global workqueue. However, the kevent has not yet been scheduled when the usbnet device is unregistered. Therefore, executing free_netdev() results in the "free active object (kevent)" error reported here. 2. Another factor is that when calling usbnet_disconnect()->unregister_netdev(), if the usbnet device is up, ndo_stop() is executed to cancel the kevent. However, because the device is not up, ndo_stop() is not executed. The solution to this problem is to cancel the kevent before executing free_netdev().

Affected products

Linux kernel: from 5.4.211 before 5.4.302; from 5.10.137 before 5.10.247; from 5.15.61 before 5.15.197; from 4.9.326 before 4.10; from 4.14.291 before 4.15; from 4.19.256 before 4.20 — fixed in 4.10, 4.15, 4.20, 5.10.247, 5.15.197, 5.19

How to fix

Upgrade to a fixed version: Linux kernel 4.10, 4.15, 4.20, 5.10.247. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2025-68312 or the next vulnerability affects your stack