CVE-2026-98729 x86/mm: Don't apply va_align to hugetlb mappings on AMD F15h
A local attacker can trigger a kernel BUG_ON crash on specific AMD CPUs by exploiting incorrect huge page alignment logic, causing a denial of service.
- 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-2026-98729?
CVE-2026-98729 is a denial of service vulnerability in Linux, published on 18 Oct 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:
x86/mm: Don't apply va_align to hugetlb mappings on AMD F15h
get_align_mask() returns huge_page_mask_align() for hugetlbfs, but get_align_bits() adds va_align.bits regardless, so vm_unmapped_area() returns an address off the huge page boundary and __unmap_hugepage_range() hits BUG_ON(start & ~huge_page_mask(h)) at teardown.
This can be triggered on Carrizo and FX-8370E, both hstates.
Pass the file to get_align_bits() and skip the randomisation for hugetlbfs.
[ bp: Massage commit message. ]
Which versions are affected by CVE-2026-98729?
How do I fix CVE-2026-98729?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-98729 being exploited?
There is no known exploitation of CVE-2026-98729 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-98729, DEBIAN-CVE-2026-98729, GHSA-c8p2-ffwx-rgc9, UBUNTU-CVE-2026-98729.