CVE-2023-52439: Linux Kernel

High severity, CVSS 7.8. EPSS: 0.3% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: uio: Fix use-after-free in uio_open core-1 core-2 ------------------------------------------------------- uio_unregister_device uio_open idev = idr_find() device_unregister(&idev->dev) put_device(&idev->dev) uio_device_release get_device(&idev->dev) kfree(idev) uio_free_minor(minor) uio_release put_device(&idev->dev) kfree(idev) ------------------------------------------------------- In the core-1 uio_unregister_device(), the device_unregister will kfree idev when the idev->dev kobject ref is 1. But after core-1 device_unregister, put_device and before doing kfree, the core-2 may get_device. Then: 1. After core-1 kfree idev, the core-2 will do use-after-free for idev. 2. When core-2 do uio_release and put_device, the idev will be double freed. To address this issue, we can get idev atomic & inc idev reference with minor_lock.

Affected products

• Linux Linux Kernel: after 4.18.0, before 4.19.306 (fixed in 4.19.306); from 4.20.0, before 5.4.268 (fixed in 5.4.268); from 5.5.0, before 5.10.209 (fixed in 5.10.209); from 5.11.0, before 5.15.148 (fixed in 5.15.148); from 5.16.0, before 6.1.74 (fixed in 6.1.74); from 6.2.0, before 6.6.13 (fixed in 6.6.13); …

Published 2024-02-20. Last modified 2026-08-04.