# CVE-2026-53025: greybus: raw: fix use-after-free on cdev close

> A use-after-free in the Linux kernel greybus raw driver allows local attackers to cause a system crash or potentially execute code when closing a character device.

- **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 Jun 2026
- **Updated:** 21 Oct 2026
- **Also known as:** BELL-CVE-2026-53025, DEBIAN-CVE-2026-53025, GHSA-4c74-g9cq-vhc5, ROOT-OS-DEBIAN-11-CVE-2026-53025, ROOT-OS-DEBIAN-12-CVE-2026-53025, ROOT-OS-DEBIAN-13-CVE-2026-53025, ROOT-OS-UBUNTU-2204-CVE-2026-53025, ROOT-OS-UBUNTU-2404-CVE-2026-53025, UBUNTU-CVE-2026-53025

## What is CVE-2026-53025?

CVE-2026-53025 is a high-severity use after free vulnerability in Linux kernel, published on 24 Jun 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:

greybus: raw: fix use-after-free on cdev close

This addresses a use-after-free bug when a raw bundle is disconnected
but its chardev is still opened by an application. When the application
releases the cdev, it causes the following panic when init on free is
enabled (CONFIG_INIT_ON_FREE_DEFAULT_ON=y):

        refcount_t: underflow; use-after-free.
        WARNING: CPU: 0 PID: 139 at lib/refcount.c:28 refcount_warn_saturate+0xd0/0x130
         ...
        Call Trace:
         <TASK>
         cdev_put+0x18/0x30
         __fput+0x255/0x2a0
         __x64_sys_close+0x3d/0x80
         do_syscall_64+0xa4/0x290
         entry_SYSCALL_64_after_hwframe+0x77/0x7f

The cdev is contained in the "gb_raw" structure, which is freed in the
disconnect operation. When the cdev is released at a later time,
cdev_put gets an address that points to freed memory.

To fix this use-after-free, convert the struct device from a pointer to
being embedded, that makes the lifetime of the cdev and of this device
the same. Then, use cdev_device_add, which guarantees that the device
won't be released until all references to the cdev have been released.
Finally, delegate the freeing of the structure to the device release
function, instead of freeing immediately in the disconnect callback.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-53025?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53025?

Apply the vendor's patch.

## Is CVE-2026-53025 being exploited?

There is no known exploitation of CVE-2026-53025 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-2026-53025 and fix it if it is affected.

What it is: CVE-2026-53025 is a high-severity use after free vulnerability in Linux kernel, published on 24 Jun 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-2026-53025 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-2026-53025/ (Markdown: https://insights.sbomify.com/CVE-2026-53025/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53025
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53025
- OSV: https://osv.dev/vulnerability/CVE-2026-53025

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53025/
Summaries are generated and may contain mistakes; the official description above is the record.