# CVE-2026-63977: dpll: zl3073x: use __dpll_device_change_ntf() and remove change_work

> A race condition in the Linux kernel DPLL driver could cause a null pointer dereference during device teardown, leading to a system crash.

- **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:** 19 Jul 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-63977, DEBIAN-CVE-2026-63977, GHSA-665c-mwm9-rw7p, UBUNTU-CVE-2026-63977

## What is CVE-2026-63977?

CVE-2026-63977 is a high-severity vulnerability in Linux, published on 19 Jul 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:

dpll: zl3073x: use __dpll_device_change_ntf() and remove change_work

The change_work was introduced to send device change notifications
from DPLL device callbacks without deadlocking on dpll_lock, since
the callbacks are already invoked under that lock. Now that
__dpll_device_change_ntf() is exported for callers that already
hold dpll_lock, use it directly and remove the change_work
infrastructure entirely.

This eliminates a race condition where change_work could be
re-scheduled after cancel_work_sync() during device teardown,
potentially causing the handler to dereference a freed or NULL
dpll_dev pointer.

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2026-63977?


## How do I fix CVE-2026-63977?

Apply the vendor's patch.

## Is CVE-2026-63977 being exploited?

There is no known exploitation of CVE-2026-63977 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63977 and fix it if it is affected.

What it is: CVE-2026-63977 is a high-severity vulnerability in Linux, published on 19 Jul 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-2026-63977 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-2026-63977/ (Markdown: https://insights.sbomify.com/CVE-2026-63977/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63977
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63977
- OSV: https://osv.dev/vulnerability/CVE-2026-63977

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63977/
Summaries are generated and may contain mistakes; the official description above is the record.