# CVE-2018-10896: Misconfiguration in cloud-init

> Default cloud-init settings disable SSH key deletion, allowing cloned instances to share keys and enabling man-in-the-middle attacks.

- **Severity:** Medium 4.6 (`CVSS:3.0/AV:L/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 1 Aug 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-rwhw-r234-9p3m, RHSA-2020:3050, RHSA-2020:3644

## What is CVE-2018-10896?

CVE-2018-10896 is a medium-severity vulnerability in Canonical cloud-init, published on 1 Aug 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 default cloud-init configuration, in cloud-init 0.6.2 and newer, included "ssh_deletekeys: 0", disabling cloud-init's deletion of ssh host keys. In some environments, this could lead to instances created by cloning a golden master or template system, sharing ssh host keys, and being able to impersonate one another or conduct man-in-the-middle attacks.

Weakness: CWE-321 (Use of Hard-coded Cryptographic Key)

## Which versions are affected by CVE-2018-10896?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `cloud-init` | Red Hat:enterprise_linux:8::appstream | All versions | 0:19.4-1.el8.7 |
| `cloud-init` | Red Hat:rhel_eus:8.2::appstream | All versions | 0:18.5-12.el8_2.3 |

Products: Canonical Cloud-Init.

## How do I fix CVE-2018-10896?

Change a configuration setting.

## Is CVE-2018-10896 being exploited?

There is no known exploitation of CVE-2018-10896 in the wild and no public exploit code.

## Other vulnerabilities in Canonical cloud-init

- [CVE-2024-6174](https://insights.sbomify.com/CVE-2024-6174/): Hardcoded credentials in cloud-init (high 8.8)
- [CVE-2012-6639](https://insights.sbomify.com/CVE-2012-6639/): Privilege escalation in cloud-init (high 8.8)
- [CVE-2024-11584](https://insights.sbomify.com/CVE-2024-11584/): Privilege escalation in cloud-init (medium 5.9)
- [CVE-2023-1786](https://insights.sbomify.com/CVE-2023-1786/): sensitive data exposure in cloud-init logs (medium 5.5)
- [CVE-2021-3429](https://insights.sbomify.com/CVE-2021-3429/): sensitive data exposure in cloud-init logs (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-10896 and fix it if it is affected.

What it is: CVE-2018-10896 is a medium-severity vulnerability in Canonical cloud-init, published on 1 Aug 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-2018-10896 in the wild and no public exploit code.

Affected product: Canonical cloud-init. 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-2018-10896/ (Markdown: https://insights.sbomify.com/CVE-2018-10896/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-10896
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-10896
- OSV: https://osv.dev/vulnerability/CVE-2018-10896

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-10896/
Summaries are generated and may contain mistakes; the official description above is the record.