# CVE-2021-3429: sensitive data exposure in cloud-init logs

> Local attackers can read world-readable logs to obtain random passwords, enabling unauthorized login as other users.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **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:** 19 Apr 2023
- **Updated:** 5 Feb 2025
- **Also known as:** CLEANSTART-2024-OZ46983, DEBIAN-CVE-2021-3429, DLA-2601-1, GHSA-jj89-4799-j2qv, MGASA-2021-0494, OESA-2021-1372, RHSA-2021:3081, RHSA-2021:3177, RHSA-2021:3371, RLSA-2021:3081, UBUNTU-CVE-2021-3429

## What is CVE-2021-3429?

CVE-2021-3429 is a medium-severity vulnerability in Canonical Ltd. cloud-init, published on 19 Apr 2023. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

When instructing cloud-init to set a random password for a new user account, versions before 21.2 would write that password to the world-readable log file /var/log/cloud-init-output.log. This could allow a local user to log in as another user.

Weakness: CWE-532 (Insertion of Sensitive Information into Log File)

## Which versions are affected by CVE-2021-3429?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `cloud-init` | Red Hat:enterprise_linux:8::appstream | All versions | 0:20.3-10.el8_4.5 |
| `cloud-init` | Red Hat:rhel_eus:8.1::appstream | All versions | 0:18.5-7.el8_1.6 |
| `cloud-init` | Red Hat:rhel_eus:8.2::appstream | All versions | 0:18.5-12.el8_2.10 |
| `cloud-init` | Rocky Linux:8 | All versions | 0:20.3-10.el8_4.5 |

Products: Canonical Cloud-Init.

## How do I fix CVE-2021-3429?

Upgrade to a fixed version.

## Is CVE-2021-3429 being exploited?

There is no known exploitation of CVE-2021-3429 in the wild and no public exploit code.

## Other vulnerabilities in Canonical Ltd. 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-2022-2084](https://insights.sbomify.com/CVE-2022-2084/): sensitive data exposure in cloud-init logs (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-3429 and fix it if it is affected.

What it is: CVE-2021-3429 is a medium-severity vulnerability in Canonical Ltd. cloud-init, published on 19 Apr 2023. 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-2021-3429 in the wild and no public exploit code.

Affected product: Canonical Ltd. 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-2021-3429/ (Markdown: https://insights.sbomify.com/CVE-2021-3429/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3429
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3429
- OSV: https://osv.dev/vulnerability/CVE-2021-3429

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3429/
Summaries are generated and may contain mistakes; the official description above is the record.