# CVE-2021-0218: Junos OS: Command injection vulnerability in license-check daemon

> A local authenticated attacker can execute arbitrary commands with root privileges via the license-check daemon in Junos OS.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** No
- **Published:** 15 Jan 2021
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-9678-97g2-v2v3

## What is CVE-2021-0218?

CVE-2021-0218 is a high-severity command injection vulnerability in Juniper Junos, published on 15 Jan 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A command injection vulnerability in the license-check daemon of Juniper Networks Junos OS that may allow a locally authenticated attacker with low privileges to execute commands with root privilege. license-check is a daemon used to manage licenses in Junos OS. To update licenses, a user executes the command 'request system license update' via the CLI. An attacker with access to this CLI command may be able to exploit the vulnerability. This issue affects Juniper Networks Junos OS: 17.3 versions prior to 17.3R3-S9; 17.4 versions prior to 17.4R2-S12, 17.4R3-S3; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R3-S6; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R3-S6; 19.1 versions prior to 19.1R1-S6, 19.1R2-S2, 19.1R3-S3; 19.2 versions prior to 19.2R3-S1; 19.3 versions prior to 19.3R2-S5, 19.3R3; 19.4 versions prior to 19.4R2-S2, 19.4R3; 20.1 versions prior to 20.1R1-S4, 20.1R2; 20.2 versions prior to 20.2R1-S2, 20.2R2.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2021-0218?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2021-0218?

No fix has been published for CVE-2021-0218 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-0218 being exploited?

There is no known exploitation of CVE-2021-0218 in the wild and no public exploit code.

## Other vulnerabilities in Juniper Junos

- [CVE-2023-36845](https://insights.sbomify.com/CVE-2023-36845/): Juniper Junos OS EX Series and SRX Series PHP External Variable Modification (critical 9.8, exploited in the wild)
- [CVE-2020-1631](https://insights.sbomify.com/CVE-2020-1631/): Juniper Junos OS Path Traversal (high 8.8, exploited in the wild)
- [CVE-2025-21590](https://insights.sbomify.com/CVE-2025-21590/): Juniper Junos OS Improper Isolation or Compartmentalization (medium 6.7, exploited in the wild)
- [CVE-2023-36851](https://insights.sbomify.com/CVE-2023-36851/): Juniper Junos OS SRX Series Missing Authentication for Critical Function (medium 5.3, exploited in the wild)
- [CVE-2023-36844](https://insights.sbomify.com/CVE-2023-36844/): Juniper Junos OS EX Series PHP External Variable Modification (medium 5.3, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-0218 and fix it if it is affected.

What it is: CVE-2021-0218 is a high-severity command injection vulnerability in Juniper Junos, published on 15 Jan 2021. 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-2021-0218 in the wild and no public exploit code.

Affected product: Juniper Junos. 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-2021-0218/ (Markdown: https://insights.sbomify.com/CVE-2021-0218/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-0218
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-0218
- OSV: https://osv.dev/vulnerability/CVE-2021-0218

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-0218/
Summaries are generated and may contain mistakes; the official description above is the record.