# CVE-2026-80927: timekeeping: Check the return value of tk_get_aux_ts64 in __do_adjtimex()

> A race condition in the Linux kernel timekeeping subsystem allows local attackers to leak uninitialized stack data to userspace.

- **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:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-80927, DEBIAN-CVE-2026-80927, GHSA-g365-rm76-m26c, UBUNTU-CVE-2026-80927

## What is CVE-2026-80927?

CVE-2026-80927 is a 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:

timekeeping: Check the return value of tk_get_aux_ts64 in __do_adjtimex()

If the auxiliary clock is disabled during tk_get_aux_ts64() but is enabled
before tks->clock_valid is checked, then uninitialized stackdata will be
used in the calculations and indirectly leaked to userspace.

The same race window also exists after this change and also for the core
timekeeper. But in these cases the only effect would be incorrect
adjustments and this is userspace's responsibility to avoid this.

## Which versions are affected by CVE-2026-80927?


## How do I fix CVE-2026-80927?

Apply the vendor's patch.

## Is CVE-2026-80927 being exploited?

There is no known exploitation of CVE-2026-80927 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80927 and fix it if it is affected.

What it is: CVE-2026-80927 is a 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-2026-80927 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-2026-80927/ (Markdown: https://insights.sbomify.com/CVE-2026-80927/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80927
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80927
- OSV: https://osv.dev/vulnerability/CVE-2026-80927

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80927/
Summaries are generated and may contain mistakes; the official description above is the record.