# CVE-2026-80991: net: ravb: serialize PTP clock teardown

> A race condition in the Linux kernel's ravb network driver allows a use-after-free of the PTP clock, potentially leading to code execution or system crashes.

- **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:** 21 Oct 2026
- **Also known as:** AZL-100130, BELL-CVE-2026-80991, DEBIAN-CVE-2026-80991, GHSA-h2g3-mgp6-wj27, UBUNTU-CVE-2026-80991

## What is CVE-2026-80991?

CVE-2026-80991 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:

net: ravb: serialize PTP clock teardown

ravb_ptp_interrupt() can race with ravb_ptp_stop() and pass the clock to
ptp_clock_event() while ptp_clock_unregister() is freeing it. This can
lead to a use-after-free.

Use READ_ONCE() and WRITE_ONCE() for lockless access to the clock pointer.
Atomically detach it with xchg() before disabling PTP interrupts, then
synchronize all IRQs which can invoke ravb_ptp_interrupt() before
unregistering the detached clock.

A handler which read the old pointer completes before the clock is
unregistered, while later handlers read NULL and skip the event.

## Which versions are affected by CVE-2026-80991?


## How do I fix CVE-2026-80991?

Apply the vendor's patch.

## Is CVE-2026-80991 being exploited?

There is no known exploitation of CVE-2026-80991 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80991 and fix it if it is affected.

What it is: CVE-2026-80991 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-2026-80991 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-2026-80991/ (Markdown: https://insights.sbomify.com/CVE-2026-80991/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80991
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80991
- OSV: https://osv.dev/vulnerability/CVE-2026-80991

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80991/
Summaries are generated and may contain mistakes; the official description above is the record.