# CVE-2025-68250: hung_task: fix warnings caused by unaligned lock pointers

> A flaw in the Linux kernel's blocker tracking mechanism causes warnings on architectures with low memory alignment, potentially leading to system instability or denial of service.

- **Severity:** High 8.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Dec 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2025-68250, DEBIAN-CVE-2025-68250, GHSA-pxw3-4w95-6fmq, UBUNTU-CVE-2025-68250

## What is CVE-2025-68250?

CVE-2025-68250 is a high-severity denial of service vulnerability in Linux, published on 16 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

hung_task: fix warnings caused by unaligned lock pointers

The blocker tracking mechanism assumes that lock pointers are at least
4-byte aligned to use their lower bits for type encoding.

However, as reported by Eero Tamminen, some architectures like m68k
only guarantee 2-byte alignment of 32-bit values. This breaks the
assumption and causes two related WARN_ON_ONCE checks to trigger.

To fix this, the runtime checks are adjusted to silently ignore any lock
that is not 4-byte aligned, effectively disabling the feature in such
cases and avoiding the related warnings.

Thanks to Geert Uytterhoeven for bisecting!

## Which versions are affected by CVE-2025-68250?


## How do I fix CVE-2025-68250?

Apply the vendor's patch.

## Is CVE-2025-68250 being exploited?

There is no known exploitation of CVE-2025-68250 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68250 and fix it if it is affected.

What it is: CVE-2025-68250 is a high-severity denial of service vulnerability in Linux, published on 16 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-68250 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-2025-68250/ (Markdown: https://insights.sbomify.com/CVE-2025-68250/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68250
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68250
- OSV: https://osv.dev/vulnerability/CVE-2025-68250

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68250/
Summaries are generated and may contain mistakes; the official description above is the record.