# CVE-2025-21596: Junos OS: SRX1500,SRX4100,SRX4200: Execution of low-privileged CLI command results in chassisd crash

> A local low-privileged attacker can crash the chassis daemon via a CLI command, causing a denial of service on Juniper SRX devices.

- **Severity:** Medium 6.8 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/AU:N/R:U/RE:M`)
- **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:** 9 Jan 2025
- **Updated:** 9 Jan 2025
- **Also known as:** GHSA-rxq5-5w2f-g92r

## What is CVE-2025-21596?

CVE-2025-21596 is a medium-severity denial of service vulnerability in Juniper Junos, published on 9 Jan 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An Improper Handling of Exceptional Conditions vulnerability in the command-line processing of Juniper Networks Junos OS on SRX1500, SRX4100, and SRX4200 devices allows a local, low-privileged authenticated attacker executing the 'show chassis environment pem' command to cause the chassis daemon (chassisd) to crash and restart, resulting in a temporary Denial of Service (DoS). However, repeated execution of this command will eventually cause the chassisd process to fail to restart, impacting packet processing on the system.

This issue affects Junos OS on SRX1500, SRX4100, SRX4200: 

  *  All versions before 21.4R3-S9, 
  *  from 22.2 before 22.2R3-S5, 
  *  from 22.3 before 22.3R3-S4, 
  *  from 22.4 before 22.4R3-S4, 
  *  from 23.2 before 23.2R2-S3, 
  *  from 23.4 before 23.4R2-S1.

Weakness: CWE-755 (Improper Handling of Exceptional Conditions)

## Which versions are affected by CVE-2025-21596?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2025-21596?

No fix has been published for CVE-2025-21596 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-21596 being exploited?

There is no known exploitation of CVE-2025-21596 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-2025-21596 and fix it if it is affected.

What it is: CVE-2025-21596 is a medium-severity denial of service vulnerability in Juniper Junos, published on 9 Jan 2025. 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-2025-21596 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-2025-21596/ (Markdown: https://insights.sbomify.com/CVE-2025-21596/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-21596
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-21596
- OSV: https://osv.dev/vulnerability/CVE-2025-21596

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-21596/
Summaries are generated and may contain mistakes; the official description above is the record.