CVE-2026-31578 media: as102: fix to not free memory after the device is registered in as102_usb_probe()
A race condition in the as102 USB driver allows a use-after-free and double-free, potentially enabling local privilege escalation or code execution.
- 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-2026-31578?
CVE-2026-31578 is a high-severity use after free vulnerability in Linux kernel, published on 24 Apr 2026. 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:
media: as102: fix to not free memory after the device is registered in as102_usb_probe()
In as102_usb driver, the following race condition occurs: ``` CPU0 CPU1 as102_usb_probe() kzalloc(); // alloc as102_dev_t .... usb_register_dev(); fd = sys_open("/path/to/dev"); // open as102 fd .... usb_deregister_dev(); .... kfree(); // free as102_dev_t .... sys_close(fd); as102_release() // UAF!! as102_usb_release() kfree(); // DFB!! ```
When a USB character device registered with usb_register_dev() is later unregistered (via usb_deregister_dev() or disconnect), the device node is removed so new open() calls fail. However, file descriptors that are already open do not go away immediately: they remain valid until the last reference is dropped and the driver's .release() is invoked.
In as102, as102_usb_probe() calls usb_register_dev() and then, on an error path, does usb_deregister_dev() and frees as102_dev_t right away. If userspace raced a successful open() before the deregistration, that open FD will later hit as102_release() --> as102_usb_release() and access or free as102_dev_t again, occur a race to use-after-free and double-free vuln.
The fix is to never kfree(as102_dev_t) directly once usb_register_dev() has succeeded. After deregistration, defer freeing memory to .release().
In other words, let release() perform the last kfree when the final open FD is closed.
Weakness: CWE-416
Which versions are affected by CVE-2026-31578?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-31578?
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-2026-31578 being exploited?
There is no known exploitation of CVE-2026-31578 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-83861, BELL-CVE-2026-31578, DEBIAN-CVE-2026-31578, GHSA-wrgv-v45w-6gxv, ROOT-OS-DEBIAN-11-CVE-2026-31578, ROOT-OS-DEBIAN-12-CVE-2026-31578 and 3 more.