# CVE-2021-22212: Weak cryptography in ntpsec

> NTPsec allows generation of keys with special characters that are mishandled, leading to weak keys and potential man-in-the-middle attacks.

- **Severity:** Medium 4.0 (`CVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 8 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-22212, GHSA-57r9-f9gp-9f2x

## What is CVE-2021-22212?

CVE-2021-22212 is a medium-severity vulnerability in Fedoraproject Fedora, published on 8 Jun 2021. 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

ntpkeygen can generate keys that ntpd fails to parse. NTPsec 1.2.0 allows ntpkeygen to generate keys with '#' characters. ntpd then either pads, shortens the key, or fails to load these keys entirely, depending on the key type and the placement of the '#'. This results in the administrator not being able to use the keys as expected or the keys are shorter than expected and easier to brute-force, possibly resulting in MITM attacks between ntp clients and ntp servers. For short AES128 keys, ntpd generates a warning that it is padding them.

Weakness: CWE-327 (Use of a Broken or Risky Cryptographic Algorithm)

## Which versions are affected by CVE-2021-22212?

It affects 2 products.


Products: Fedoraproject Fedora, Ntpsec Ntpsec.

## How do I fix CVE-2021-22212?

Upgrade to a fixed version.

## Is CVE-2021-22212 being exploited?

There is no known exploitation of CVE-2021-22212 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-22212 and fix it if it is affected.

What it is: CVE-2021-22212 is a medium-severity vulnerability in Fedoraproject Fedora, published on 8 Jun 2021. 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-2021-22212 in the wild and no public exploit code.

Affected product: Fedoraproject Fedora. 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-2021-22212/ (Markdown: https://insights.sbomify.com/CVE-2021-22212/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-22212
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-22212
- OSV: https://osv.dev/vulnerability/CVE-2021-22212

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-22212/
Summaries are generated and may contain mistakes; the official description above is the record.