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.
- 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
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.
Sources
Also known as DEBIAN-CVE-2026-72180, GHSA-fr6m-54gx-w628, UBUNTU-CVE-2026-72180.