# CVE-2026-89900: media: cec: core: Fix kmemleak due to missed rc_free_device() call

> A memory leak in the Linux kernel CEC driver can lead to resource exhaustion and denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-101120, BELL-CVE-2026-89900, DEBIAN-CVE-2026-89900, GHSA-3cp8-qx5m-j98g, UBUNTU-CVE-2026-89900

## What is CVE-2026-89900?

CVE-2026-89900 is a memory corruption vulnerability in Linux, published on 16 Sep 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: cec: core: Fix kmemleak due to missed rc_free_device() call

The commit dccc0c3ddf8f ("media: rc: fix race between unregister and
urb/irq callbacks") removed the implicit call to rc_free_device() from
rc_unregister_device(). However, the commit missed to remove the NULL
assignment of adap->rc that is now causing rc_free_device() to never be
called on an allocated rc device.

kmemleak reports following after e.g. dw-hdmi unbind:

unreferenced object 0xffff00010ac10000 (size 4096):
  comm "kworker/u16:1", pid 39, jiffies 4294897739
  hex dump (first 32 bytes):
    20 23 4b 0a 01 00 ff ff 08 00 c1 0a 01 00 ff ff   #K.............
    08 00 c1 0a 01 00 ff ff 00 00 00 00 00 00 00 00  ................
  backtrace (crc e11baccc):
    kmemleak_alloc+0x38/0x44
    __kmalloc_cache_noprof+0x4a8/0x5e0
    rc_allocate_device+0x48/0x2a0
    cec_allocate_adapter+0x3ac/0x800
    dw_hdmi_cec_probe+0x264/0x634
    platform_probe+0xc0/0x188
    really_probe+0x4a4/0x8e0
    __driver_probe_device+0x2f8/0x440
    driver_probe_device+0x60/0x160
    __device_attach_driver+0x1a0/0x2a0
    bus_for_each_drv+0x100/0x1a0
    __device_attach+0x174/0x350
    device_initial_probe+0x90/0xb0
    bus_probe_device+0x4c/0x120
    device_add+0xdec/0x116c
    platform_device_add+0x354/0x598

Remove the assignment of adap->rc to NULL to let cec_delete_adapter()
free the allocated rc device after last user of the cec device exits to
fix the kmemleak.

## Which versions are affected by CVE-2026-89900?


## How do I fix CVE-2026-89900?

Apply the vendor's patch.

## Is CVE-2026-89900 being exploited?

There is no known exploitation of CVE-2026-89900 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89900 and fix it if it is affected.

What it is: CVE-2026-89900 is a memory corruption vulnerability in Linux, published on 16 Sep 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-2026-89900 in the wild and no public exploit code.

Affected product: Linux. 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-2026-89900/ (Markdown: https://insights.sbomify.com/CVE-2026-89900/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89900
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89900
- OSV: https://osv.dev/vulnerability/CVE-2026-89900

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89900/
Summaries are generated and may contain mistakes; the official description above is the record.