# 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.

- **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:** 18 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-98729, DEBIAN-CVE-2026-98729, GHSA-c8p2-ffwx-rgc9, UBUNTU-CVE-2026-98729

## 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.

## Is CVE-2026-98729 being exploited?

There is no known exploitation of CVE-2026-98729 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98729 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-98729 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-2026-98729/ (Markdown: https://insights.sbomify.com/CVE-2026-98729/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98729
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98729
- OSV: https://osv.dev/vulnerability/CVE-2026-98729

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98729/
Summaries are generated and may contain mistakes; the official description above is the record.