CVE-2023-52439 uio: Fix use-after-free in uio_open
A race condition in the Linux kernel UIO driver allows a local attacker to trigger a use-after-free, potentially leading to code execution or privilege escalation.
- 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-2023-52439?
CVE-2023-52439 is a high-severity use after free vulnerability in Linux kernel, published on 20 Feb 2024. 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:
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.
Weakness: CWE-415
Which versions are affected by CVE-2023-52439?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-52439?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2023-52439 being exploited?
There is no known exploitation of CVE-2023-52439 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2023-52439, DEBIAN-CVE-2023-52439, GHSA-7gq6-cq6r-rrpx, UBUNTU-CVE-2023-52439.