# CVE-2026-93232: mm/hugetlb: fix boot panic with CONFIG_DEBUG_VM and HVO bootmem pages

> A kernel bug causes a boot panic when CONFIG_DEBUG_VM and HVO are enabled, leading to denial of service during system startup.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-93232, GHSA-rjqq-v75c-fv5f, UBUNTU-CVE-2026-93232

## What is CVE-2026-93232?

CVE-2026-93232 is a denial of service vulnerability in Linux, published on 24 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/hugetlb: fix boot panic with CONFIG_DEBUG_VM and HVO bootmem pages

Patch series "mm: Refactor bootmem gigantic hugepage allocation", v4.

This series is split out from the earlier larger series "mm: Generalize
HVO for HugeTLB and device DAX" [1].  It collects the first 19 patches of
that series as a standalone set of fixes and preparatory cleanups around
bootmem HugeTLB handling, sparse initialization ordering, and related
vmemmap setup.

The first patches fix a few bugs found while reviewing the existing code,
including incorrect bootmem HVO handling, wrong vmemmap registration
arguments, a powerpc compound-vmemmap tracking bug, and too-late
initialization of gigantic bootmem HugeTLB struct pages.

The rest of the series reorders early memory initialization so the
relevant zone state is available before sparse and HugeTLB boot-time setup
runs, then simplifies the remaining bootmem gigantic hugepage allocation
path and removes code made obsolete by that rework.

At a high level:
  - patches [1-4] fix boot-time and arch-specific bugs
  - patches [5-12] reorder and simplify sparse/mm/hugetlb early init
  - patches [13-19] refactor bootmem gigantic hugepage allocation and
    remove obsolete helpers and state

This patch (of 19):

Commit 622026e87c40 ("mm/hugetlb: remove fake head pages") switched
HVO to reuse per-zone shared tail pages from zone->vmemmap_tails[].

Those shared tail pages were initialized in hugetlb_vmemmap_init(), but
bootmem HugeTLB folios are prepared earlier from
gather_bootmem_prealloc().  With hugetlb_free_vmemmap=on,
prep_and_add_bootmem_folios() can access pageblock flags on bootmem
HugeTLB pages whose mirrored tail struct pages already point to the shared
tail page.  On CONFIG_DEBUG_VM kernels, get_pfnblock_bitmap_bitidx() then
dereferences the still-uninitialized shared tail page and can panic during
boot.

Initialize zone->vmemmap_tails[] from gather_bootmem_prealloc(), before
bootmem HugeTLB folios are processed, and drop the later initialization
from hugetlb_vmemmap_init().

This bug only affects CONFIG_DEBUG_VM kernels, where the relevant
assertion is evaluated.

## Which versions are affected by CVE-2026-93232?


## How do I fix CVE-2026-93232?

Apply the vendor's patch.

## Is CVE-2026-93232 being exploited?

There is no known exploitation of CVE-2026-93232 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93232 and fix it if it is affected.

What it is: CVE-2026-93232 is a denial of service vulnerability in Linux, published on 24 Sep 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-2026-93232 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-2026-93232/ (Markdown: https://insights.sbomify.com/CVE-2026-93232/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93232
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93232
- OSV: https://osv.dev/vulnerability/CVE-2026-93232

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93232/
Summaries are generated and may contain mistakes; the official description above is the record.