# CVE-2026-89585: auxdisplay: charlcd: cancel backlight work on registration failure

> A use-after-free vulnerability in the Linux kernel charlcd driver allows attackers to cause denial of service or execute code if backlight flashing is enabled and registration fails.

- **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:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-100451, BELL-CVE-2026-89585, DEBIAN-CVE-2026-89585, GHSA-72rp-5pw2-wrgc, UBUNTU-CVE-2026-89585

## What is CVE-2026-89585?

CVE-2026-89585 is a high-severity use after free vulnerability in Linux, published on 11 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:

auxdisplay: charlcd: cancel backlight work on registration failure

With CONFIG_CHARLCD_BL_FLASH, charlcd_init() schedules bl_work before
charlcd_register() calls misc_register(). If registration fails, the
caller frees the charlcd object while delayed work still contains its
address.

Add charlcd_deinit() to cancel the delayed work and turn the backlight
off. Use it for both registration rollback and normal unregistration.

## Which versions are affected by CVE-2026-89585?


## How do I fix CVE-2026-89585?

Apply the vendor's patch.

## Is CVE-2026-89585 being exploited?

There is no known exploitation of CVE-2026-89585 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89585 and fix it if it is affected.

What it is: CVE-2026-89585 is a high-severity use after free vulnerability in Linux, published on 11 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-2026-89585 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-2026-89585/ (Markdown: https://insights.sbomify.com/CVE-2026-89585/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89585
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89585
- OSV: https://osv.dev/vulnerability/CVE-2026-89585

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89585/
Summaries are generated and may contain mistakes; the official description above is the record.