# CVE-2026-63953: mm/migrate_device: fix pgtable leak in migrate_vma_insert_huge_pmd_page

> A memory leak in the Linux kernel's device migration code allows attackers to exhaust system memory, leading to denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Not stated
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Jul 2026
- **Updated:** 19 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-63953, GHSA-68mw-455j-vxm4, UBUNTU-CVE-2026-63953

## What is CVE-2026-63953?

CVE-2026-63953 is a memory corruption vulnerability in Linux, published on 19 Jul 2026. 

### Official description

In the Linux kernel, the following vulnerability has been resolved:

mm/migrate_device: fix pgtable leak in migrate_vma_insert_huge_pmd_page

When migrate_vma_insert_huge_pmd_page() jumps to unlock_abort due
to a PMD check failure, the pgtable allocated earlier via
pte_alloc_one() is never freed, causing a memory leak.

Added free_abort label to release the pgtable in error path.

## Which versions are affected by CVE-2026-63953?


## How do I fix CVE-2026-63953?

Apply the vendor's patch.

## Is CVE-2026-63953 being exploited?

There is no known exploitation of CVE-2026-63953 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63953 and fix it if it is affected.

What it is: CVE-2026-63953 is a memory corruption vulnerability in Linux, published on 19 Jul 2026. 
Exploitation: There is no known exploitation of CVE-2026-63953 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-2026-63953/ (Markdown: https://insights.sbomify.com/CVE-2026-63953/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63953
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63953
- OSV: https://osv.dev/vulnerability/CVE-2026-63953

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63953/
Summaries are generated and may contain mistakes; the official description above is the record.