# CVE-2026-97963: net: stmmac: initialize ptp_lock at probe time

> An uninitialized lock in the stmmac network driver can cause a kernel crash when configuring TAPRIO schedules on a down interface.

- **Severity:** Not scored
- **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:** 25 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-104268, BELL-CVE-2026-97963, DEBIAN-CVE-2026-97963, GHSA-rqgr-p8xr-jcx7, UBUNTU-CVE-2026-97963

## What is CVE-2026-97963?

CVE-2026-97963 is a vulnerability in Linux, published on 25 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:

net: stmmac: initialize ptp_lock at probe time

priv->ptp_lock is only initialized in stmmac_ptp_register(), which runs
during __stmmac_open(). However, the lock is also used while the
interface is down and has never been opened: tc_taprio_configure()
invokes the PTP gettime64() callback to compute the EST base time when
offloading a TAPRIO schedule, and stmmac_get_time() takes
priv->ptp_lock. Using an uninitialized rwlock is undefined behaviour.
Move the rwlock_init() to __stmmac_dvr_probe(), together with the other
private locks, so that ptp_lock is always valid regardless of the
interface state.

## Which versions are affected by CVE-2026-97963?


## How do I fix CVE-2026-97963?

Apply the vendor's patch.

## Is CVE-2026-97963 being exploited?

There is no known exploitation of CVE-2026-97963 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97963 and fix it if it is affected.

What it is: CVE-2026-97963 is a vulnerability in Linux, published on 25 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-2026-97963 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-2026-97963/ (Markdown: https://insights.sbomify.com/CVE-2026-97963/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97963
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97963
- OSV: https://osv.dev/vulnerability/CVE-2026-97963

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97963/
Summaries are generated and may contain mistakes; the official description above is the record.