# CVE-2026-98433: KVM: PPC: Book3S HV: fix secure device page leak on uv_page_in() failure

> A resource leak in Linux KVM PPC secure virtualization allows local attackers to exhaust secure memory pools, causing 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:** AZL-108734, BELL-CVE-2026-98433, DEBIAN-CVE-2026-98433, GHSA-3v64-xhg6-868f, UBUNTU-CVE-2026-98433

## What is CVE-2026-98433?

CVE-2026-98433 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:

KVM: PPC: Book3S HV: fix secure device page leak on uv_page_in() failure

In kvmppc_svm_page_in(), if uv_page_in() fails after
kvmppc_uvmem_get_page() has succeeded, the secure device page is never
released.  kvmppc_uvmem_get_page() sets a bit in kvmppc_uvmem_bitmap,
allocates a kvmppc_uvmem_page_pvt struct, marks the GFN as
KVMPPC_GFN_UVMEM_PFN, and calls zone_device_page_init() which sets
refcount=1 and locks the page.  The subsequent goto out_finalize skips
the *mig.dst assignment, so migrate_vma_finalize() is a no-op for the
page, and none of those resources are ever reclaimed.

Each occurrence permanently consumes one entry from the firmware-bounded
secure memory pool (kvmppc_uvmem_bitmap), leaks pvt, and leaves the GFN
marked as secure — making it unusable for the lifetime of the VM.

The twin __kvmppc_svm_page_out() already handles the analogous uv_page_out()
failure correctly with unlock_page(dpage); __free_page(dpage).  Apply
the same pattern here: unlock_page() followed by put_page(), which
chains through free_zone_device_folio() into kvmppc_uvmem_folio_free()
to clear the bitmap bit, free pvt, and reset the GFN state.

Reachable whenever uv_page_in() returns an error (e.g. UV pool
exhaustion) on any POWER9/10 + Ultravisor/PEF system.

## Which versions are affected by CVE-2026-98433?


## How do I fix CVE-2026-98433?

Apply the vendor's patch.

## Is CVE-2026-98433 being exploited?

There is no known exploitation of CVE-2026-98433 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98433 and fix it if it is affected.

What it is: CVE-2026-98433 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-2026-98433 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-2026-98433/ (Markdown: https://insights.sbomify.com/CVE-2026-98433/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98433
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98433
- OSV: https://osv.dev/vulnerability/CVE-2026-98433

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98433/
Summaries are generated and may contain mistakes; the official description above is the record.