# CVE-2026-80622: char: tlclk: fix use-after-free in tlclk_cleanup()

> A use-after-free vulnerability in the Linux kernel tlclk driver allows attackers to execute arbitrary code or escalate privileges during module cleanup.

- **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:** 28 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** BELL-CVE-2026-80622, DEBIAN-CVE-2026-80622, GHSA-hhvf-97x6-wjfh, UBUNTU-CVE-2026-80622

## What is CVE-2026-80622?

CVE-2026-80622 is a high-severity use after free vulnerability in Linux, published on 28 Aug 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:

char: tlclk: fix use-after-free in tlclk_cleanup()

This patch improves the module cleanup process in the tlclk driver to
prevent potential use-after-free and race conditions.

Currently, the file_operations structure does not specify the .owner
field, which could allow the module to be unloaded while user-space
processes are still interacting with the device. Additionally, the
tlclk_cleanup() function frees the alarm_events memory before ensuring
that blocked processes in the waitqueue are fully awakened and that the
switchover_timer has completed.

To address these cases, this patch:
- Sets '.owner = THIS_MODULE' in tlclk_fops to safely defer module
  unloading while the device is in use.
- Updates tlclk_cleanup() to explicitly wake up all blocked readers
  (wake_up_all), properly release hardware I/O regions, and safely
  delete the timer (timer_delete_sync) prior to freeing memory.

## Which versions are affected by CVE-2026-80622?


## How do I fix CVE-2026-80622?

Apply the vendor's patch.

## Is CVE-2026-80622 being exploited?

There is no known exploitation of CVE-2026-80622 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80622 and fix it if it is affected.

What it is: CVE-2026-80622 is a high-severity use after free vulnerability in Linux, published on 28 Aug 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-2026-80622 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-2026-80622/ (Markdown: https://insights.sbomify.com/CVE-2026-80622/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80622
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80622
- OSV: https://osv.dev/vulnerability/CVE-2026-80622

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80622/
Summaries are generated and may contain mistakes; the official description above is the record.