# CVE-2026-68178: misc: nsm: pin the module while the device is open

> An attacker with an open file descriptor can trigger a use-after-free by unloading the NSM kernel module, potentially leading to code execution or privilege escalation.

- **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:** 10 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-68178, DEBIAN-CVE-2026-68178, GHSA-785r-497w-84xv, UBUNTU-CVE-2026-68178

## What is CVE-2026-68178?

CVE-2026-68178 is a high-severity use after free vulnerability in Linux, published on 10 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:

misc: nsm: pin the module while the device is open

misc_open() installs a misc driver's file operations with fops_get(),
which pins file_operations::owner before replacing the file's f_op.  The
NSM misc device leaves nsm_dev_fops.owner unset, so opening /dev/nsm does
not take a module reference on the nsm driver.

If the driver is built as a module, an open file descriptor can therefore
survive rmmod of the module that provides its ioctl callbacks.  A later
ioctl through that descriptor can call into unloaded module text.

Set nsm_dev_fops.owner to THIS_MODULE so the misc core holds the module
while any /dev/nsm file descriptor is open, matching the lifetime
expectation for the installed file operations.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-68178?


## How do I fix CVE-2026-68178?

Apply the vendor's patch.

## Is CVE-2026-68178 being exploited?

There is no known exploitation of CVE-2026-68178 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68178 and fix it if it is affected.

What it is: CVE-2026-68178 is a high-severity use after free vulnerability in Linux, published on 10 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-2026-68178 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-2026-68178/ (Markdown: https://insights.sbomify.com/CVE-2026-68178/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68178
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68178
- OSV: https://osv.dev/vulnerability/CVE-2026-68178

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68178/
Summaries are generated and may contain mistakes; the official description above is the record.