# CVE-2020-8631: Weak cryptography in n/a

> Attackers can predict random passwords generated by cloud-init due to weak randomness, potentially leading to unauthorized access.

- **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:** 5 Feb 2020
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2020-8631, GHSA-2r47-hhff-7qcp, UBUNTU-CVE-2020-8631

## What is CVE-2020-8631?

CVE-2020-8631 is a medium-severity vulnerability in Debian Debian Linux, published on 5 Feb 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

cloud-init through 19.4 relies on Mersenne Twister for a random password, which makes it easier for attackers to predict passwords, because rand_str in cloudinit/util.py calls the random.choice function.

Weakness: CWE-330 (Use of Insufficiently Random Values)

## Which versions are affected by CVE-2020-8631?

It affects 3 products.


Products: Canonical Cloud-Init, Debian Debian Linux, Opensuse Leap.

## How do I fix CVE-2020-8631?

Apply the vendor's patch.

## Is CVE-2020-8631 being exploited?

There is no known exploitation of CVE-2020-8631 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [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-2020-8631 and fix it if it is affected.

What it is: CVE-2020-8631 is a medium-severity vulnerability in Debian Debian Linux, published on 5 Feb 2020. 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-2020-8631 in the wild and no public exploit code.

Affected product: Debian Debian 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-2020-8631/ (Markdown: https://insights.sbomify.com/CVE-2020-8631/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-8631
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-8631
- OSV: https://osv.dev/vulnerability/CVE-2020-8631

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-8631/
Summaries are generated and may contain mistakes; the official description above is the record.