# CVE-2025-21590: Juniper Junos OS Improper Isolation or Compartmentalization

> A local attacker with shell access can inject arbitrary code into the Junos OS kernel, compromising device integrity and executing code.

- **Severity:** Medium 6.7 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Yes, since 13 Mar 2025 (CISA KEV)
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Mar 2025
- **Updated:** 26 Feb 2026
- **Also known as:** GHSA-jwv5-xmf5-mp56

## What is CVE-2025-21590?

CVE-2025-21590 is a medium-severity code injection vulnerability in Juniper Junos, published on 12 Mar 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An Improper Isolation or Compartmentalization vulnerability in the kernel of Juniper Networks Junos OS allows a local attacker with high privileges to compromise the integrity of the device.

A local attacker with access to the shell is able to inject arbitrary code which can compromise an affected device.
This issue is not exploitable from the Junos CLI.
This issue affects Junos OS: 

  *  All versions before 21.2R3-S9,
  *  21.4 versions before 21.4R3-S10, 
  *  22.2 versions before 22.2R3-S6, 
  *  22.4 versions before 22.4R3-S6, 
  *  23.2 versions before 23.2R2-S3, 
  *  23.4 versions before 23.4R2-S4,
  *  24.2 versions before 24.2R1-S2, 24.2R2.

Weakness: CWE-653 (Improper Isolation or Compartmentalization)

## Which versions are affected by CVE-2025-21590?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2025-21590?

No fix has been published for CVE-2025-21590 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 3 Apr 2025.

## Is CVE-2025-21590 being exploited?

Yes. Attackers have exploited CVE-2025-21590 in the wild since at least 13 Mar 2025.

## 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-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)
- [CVE-2023-36846](https://insights.sbomify.com/CVE-2023-36846/): Juniper Junos OS SRX Series Missing Authentication for Critical Function (medium 5.3, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-21590 and fix it if it is affected.

What it is: CVE-2025-21590 is a medium-severity code injection vulnerability in Juniper Junos, published on 12 Mar 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2025-21590 in the wild since at least 13 Mar 2025.

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-2025-21590/ (Markdown: https://insights.sbomify.com/CVE-2025-21590/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-21590
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-21590
- OSV: https://osv.dev/vulnerability/CVE-2025-21590

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-21590/
Summaries are generated and may contain mistakes; the official description above is the record.