CVE-2026-89967 mm/migrate_device: avoid out-of-bounds writes for compound folios
An out-of-bounds write in the Linux kernel's device memory migration code allows attackers to potentially execute arbitrary code or escalate privileges.
- 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-2026-89967?
CVE-2026-89967 is a high-severity memory corruption vulnerability in Linux, published on 16 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:
mm/migrate_device: avoid out-of-bounds writes for compound folios
migrate_device_range() and migrate_device_pfns() clear the entries following a compound folio so that the PFN arrays retain their page-granular representation.
If a compound folio extends beyond the end of the caller-provided range, the loops clear all following folio entries without limiting them to the number of slots remaining in the npages-sized array, causing an out-of-bounds write.
Do not proceed with a compound folio if its page-granular representation does not fit entirely in the remaining PFN array. If this happens, drop any reference and lock acquired for the folio, clear the remaining entries, and stop collecting.
Observed with a KASAN x86 QEMU kernel using the HMM migrate_anon_huge_zero selftest. Closing /dev/hmm_dmirror0 after migrating an anonymous huge page to device memory exercises:
dmirror_fops_release() -> dmirror_device_evict_chunk() -> migrate_device_range()
Which versions are affected by CVE-2026-89967?
How do I fix CVE-2026-89967?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-89967 being exploited?
There is no known exploitation of CVE-2026-89967 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-89967, GHSA-mmrq-wq59-jg48, UBUNTU-CVE-2026-89967.