# 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.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 24 Apr 2026
- **Updated:** 14 Jun 2026
- **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, ROOT-OS-UBUNTU-2204-CVE-2026-31578, ROOT-OS-UBUNTU-2404-CVE-2026-31578, UBUNTU-CVE-2026-31578

## 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 (Use After Free)

## Which versions are affected by CVE-2026-31578?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31578?

Apply the vendor's patch.

## 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

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-31578 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-31578 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-31578/ (Markdown: https://insights.sbomify.com/CVE-2026-31578/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31578
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31578
- OSV: https://osv.dev/vulnerability/CVE-2026-31578

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31578/
Summaries are generated and may contain mistakes; the official description above is the record.