# CVE-2018-7191: Null dereference in n/a

> Local attackers can cause a kernel panic and denial of service via a specific ioctl call in the tun subsystem.

- **Severity:** Medium 5.5 (`CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 May 2019
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-7191, GHSA-p54q-624c-fr42, UBUNTU-CVE-2018-7191

## What is CVE-2018-7191?

CVE-2018-7191 is a medium-severity vulnerability in Linux kernel, published on 17 May 2019. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the tun subsystem in the Linux kernel before 4.13.14, dev_get_valid_name is not called before register_netdevice. This allows local users to cause a denial of service (NULL pointer dereference and panic) via an ioctl(TUNSETIFF) call with a dev name containing a / character. This is similar to CVE-2013-4343.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2018-7191?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2018-7191?

Apply the vendor's patch.

## Is CVE-2018-7191 being exploited?

There is no known exploitation of CVE-2018-7191 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-7191 and fix it if it is affected.

What it is: CVE-2018-7191 is a medium-severity vulnerability in Linux kernel, published on 17 May 2019. 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-2018-7191 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2018-7191/ (Markdown: https://insights.sbomify.com/CVE-2018-7191/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-7191
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-7191
- OSV: https://osv.dev/vulnerability/CVE-2018-7191

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-7191/
Summaries are generated and may contain mistakes; the official description above is the record.