# CVE-2026-72180: mm/huge_memory: preserve pmd_swp_uffd_wp on device-private PMD downgrade

> A local attacker can bypass userfaultfd write protection on device-private huge pages by triggering a PMD downgrade, potentially evading memory monitoring.

- **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:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-72180, GHSA-fr6m-54gx-w628, UBUNTU-CVE-2026-72180

## What is CVE-2026-72180?

CVE-2026-72180 is a vulnerability in Linux, published on 15 Aug 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:

mm/huge_memory: preserve pmd_swp_uffd_wp on device-private PMD downgrade

change_non_present_huge_pmd() rewrites a writable device-private PMD swap
entry into a readable one without carrying pmd_swp_uffd_wp() across.  The
PTE-level change_softleaf_pte() does this correctly; mirror that here,
matching what copy_huge_pmd() does for the fork path.  Without the carry,
a plain mprotect() over a UFFD_WP-marked device-private THP strips the bit
and the trap is bypassed on swap-in.

## Which versions are affected by CVE-2026-72180?


## How do I fix CVE-2026-72180?

Apply the vendor's patch.

## Is CVE-2026-72180 being exploited?

There is no known exploitation of CVE-2026-72180 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72180 and fix it if it is affected.

What it is: CVE-2026-72180 is a vulnerability in Linux, published on 15 Aug 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-2026-72180 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-2026-72180/ (Markdown: https://insights.sbomify.com/CVE-2026-72180/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72180
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72180
- OSV: https://osv.dev/vulnerability/CVE-2026-72180

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72180/
Summaries are generated and may contain mistakes; the official description above is the record.