# CVE-2026-74379: dax/kmem: account for partial discontiguous resource upon removal

> A null pointer dereference in the Linux kernel DAX/kmem driver can cause a system crash during device removal if partial memory mapping fails.

- **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:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-74379, DEBIAN-CVE-2026-74379, GHSA-wpc6-x34r-qgj2, UBUNTU-CVE-2026-74379

## What is CVE-2026-74379?

CVE-2026-74379 is a vulnerability in Linux, published on 15 Aug 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/kmem: account for partial discontiguous resource upon removal

When dev_dax_kmem_probe() partially succeeds (at least one range is
mapped) but a subsequent range fails request_mem_region() or
add_memory_driver_managed(), the probe silently continues, ultimately
returning success, but with the corresponding range resource NULL'ed out.

dev_dax_kmem_remove() iterates over all dax_device ranges regardless of if
the underlying resource exists.  When remove_memory() is called later, it
returns 0 because the memory was never added which causes
dev_dax_kmem_remove() to incorrectly assume the (nonexistent) resource can
be removed and attempts cleanup on a NULL pointer.

Fix this by skipping these ranges altogether, noting that these cases are
considered success, such that the cleanup is still reached when all
actually-added ranges are successfully removed.

## Which versions are affected by CVE-2026-74379?


## How do I fix CVE-2026-74379?

Apply the vendor's patch.

## Is CVE-2026-74379 being exploited?

There is no known exploitation of CVE-2026-74379 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74379 and fix it if it is affected.

What it is: CVE-2026-74379 is a vulnerability in Linux, published on 15 Aug 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-2026-74379 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-2026-74379/ (Markdown: https://insights.sbomify.com/CVE-2026-74379/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74379
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74379
- OSV: https://osv.dev/vulnerability/CVE-2026-74379

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74379/
Summaries are generated and may contain mistakes; the official description above is the record.