# CVE-2018-1094: Null dereference in Linux kernel through version 4.15

> Attackers can cause a system crash via a crafted ext4 image due to a NULL pointer dereference in the Linux kernel.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 2 Apr 2018
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-1094, GHSA-qqjj-7xjv-r736, UBUNTU-CVE-2018-1094

## What is CVE-2018-1094?

CVE-2018-1094 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 2 Apr 2018. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

The ext4_fill_super function in fs/ext4/super.c in the Linux kernel through 4.15.15 does not always initialize the crc32c checksum driver, which allows attackers to cause a denial of service (ext4_xattr_inode_hash NULL pointer dereference and system crash) via a crafted ext4 image.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2018-1094?

It affects 5 products.


Products: Canonical Ubuntu Linux, Linux kernel, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Server, Redhat Enterprise Linux Workstation.

## How do I fix CVE-2018-1094?

Apply the vendor's patch.

## Is CVE-2018-1094 being exploited?

There is no known exploitation of CVE-2018-1094 in the wild and no public exploit code.

## Other vulnerabilities in Canonical Ubuntu Linux

- [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild)
- [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-1094 and fix it if it is affected.

What it is: CVE-2018-1094 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 2 Apr 2018. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2018-1094 in the wild and no public exploit code.

Affected product: Canonical Ubuntu 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-2018-1094/ (Markdown: https://insights.sbomify.com/CVE-2018-1094/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-1094
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-1094
- OSV: https://osv.dev/vulnerability/CVE-2018-1094

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-1094/
Summaries are generated and may contain mistakes; the official description above is the record.