# CVE-2026-93074: dax/fsdev: use __va(phys) for kaddr in direct_access

> Incorrect kernel virtual address calculation in DAX direct access for multi-range devices could lead to memory access errors.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-93074, GHSA-hvvg-v8hj-gpv8, UBUNTU-CVE-2026-93074

## What is CVE-2026-93074?

CVE-2026-93074 is a high-severity 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: use __va(phys) for kaddr in direct_access

Use __va(phys) instead of virt_addr + linear_offset for the kaddr
return in __fsdev_dax_direct_access(). The previous code added a
device-linear byte offset to virt_addr (which is __va of ranges[0]),
but for multi-range devices with physical gaps between ranges, this
linear arithmetic crosses the gap and produces a wrong kernel virtual
address. Using __va(phys) where phys comes from dax_pgoff_to_phys()
is correct for any range layout because the direct map translates
each physical address independently.

This leaves dev_dax->virt_addr write-only, so remove the field
(suggested by Dave Jiang).

## Which versions are affected by CVE-2026-93074?


## How do I fix CVE-2026-93074?

Apply the vendor's patch.

## Is CVE-2026-93074 being exploited?

There is no known exploitation of CVE-2026-93074 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93074 and fix it if it is affected.

What it is: CVE-2026-93074 is a high-severity 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-2026-93074 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-2026-93074/ (Markdown: https://insights.sbomify.com/CVE-2026-93074/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93074
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93074
- OSV: https://osv.dev/vulnerability/CVE-2026-93074

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93074/
Summaries are generated and may contain mistakes; the official description above is the record.