# CVE-2026-93076: dax/fsdev: clear vmemmap_shift when binding static pgmap

> A stale vmemmap_shift in the Linux kernel DAX subsystem can cause memory mapping errors when rebinding devices, potentially leading to system instability or crashes.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-93076, GHSA-m5cm-762c-jpjj, UBUNTU-CVE-2026-93076

## What is CVE-2026-93076?

CVE-2026-93076 is a vulnerability in Linux, published on 17 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:

dax/fsdev: clear vmemmap_shift when binding static pgmap

Clear pgmap->vmemmap_shift for static DAX devices. When rebinding a static
device from device_dax (which may set vmemmap_shift based on alignment) to
fsdev_dax, the stale vmemmap_shift persists on the shared pgmap. Explicitly
zero it before devm_memremap_pages() so the vmemmap is built for order-0
folios as fsdev requires.

## Which versions are affected by CVE-2026-93076?


## How do I fix CVE-2026-93076?

Apply the vendor's patch.

## Is CVE-2026-93076 being exploited?

There is no known exploitation of CVE-2026-93076 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93076 and fix it if it is affected.

What it is: CVE-2026-93076 is a vulnerability in Linux, published on 17 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-2026-93076 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-2026-93076/ (Markdown: https://insights.sbomify.com/CVE-2026-93076/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93076
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93076
- OSV: https://osv.dev/vulnerability/CVE-2026-93076

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93076/
Summaries are generated and may contain mistakes; the official description above is the record.