# CVE-2024-39556: Junos OS and Junos OS Evolved: Loading a malicious certificate from the CLI may result in a stack-based overflow

> A local low-privileged attacker can trigger a stack-based buffer overflow via a malicious certificate, causing DoS or code execution.

- **Severity:** High 7.1 (`CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Jul 2024
- **Updated:** 2 Aug 2024
- **Also known as:** GHSA-4fvx-2mxh-x7v7

## What is CVE-2024-39556?

CVE-2024-39556 is a high-severity memory corruption vulnerability in Juniper Junos, published on 10 Jul 2024. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A Stack-Based Buffer Overflow vulnerability in Juniper Networks Junos OS and Juniper Networks Junos OS Evolved may allow a local, low-privileged attacker with access to the CLI the ability to load a malicious certificate file, leading to a limited Denial of Service (DoS) or privileged code execution.

By exploiting the 'set security certificates' command with a crafted certificate file, a malicious attacker with access to the CLI could cause a crash of the command management daemon (mgd), limited to the local user's command interpreter, or potentially trigger a stack-based buffer overflow.

This issue affects:

 Junos OS: 

  *  All versions before 21.4R3-S7, 
  *  from 22.1 before 22.1R3-S6, 
  *  from 22.2 before 22.2R3-S4, 
  *  from 22.3 before 22.3R3-S3, 
  *  from 22.4 before 22.4R3-S2, 
  *  from 23.2 before 23.2R2, 
  *  from 23.4 before 23.4R1-S1, 23.4R2; 

Junos OS Evolved: 

  *  All versions before 21.4R3-S7-EVO, 
  *  from 22.1-EVO before 22.1R3-S6-EVO, 
  *  from 22.2-EVO before 22.2R3-S4-EVO, 
  *  from 22.3-EVO before 22.3R3-S3-EVO, 
  *  from 22.4-EVO before 22.4R3-S2-EVO, 
  *  from 23.2-EVO before 23.2R2-EVO, 
  *  from 23.4-EVO before 23.4R1-S1-EVO, 23.4R2-EVO.

Weakness: CWE-787 (Out-of-bounds Write), CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2024-39556?

It affects 2 products.


Products: Juniper Junos, Juniper Junos Os Evolved.

## How do I fix CVE-2024-39556?

No fix has been published for CVE-2024-39556 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-39556 being exploited?

There is no known exploitation of CVE-2024-39556 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-2024-39556 and fix it if it is affected.

What it is: CVE-2024-39556 is a high-severity memory corruption vulnerability in Juniper Junos, published on 10 Jul 2024. 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-2024-39556 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-2024-39556/ (Markdown: https://insights.sbomify.com/CVE-2024-39556/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-39556
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-39556
- OSV: https://osv.dev/vulnerability/CVE-2024-39556

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-39556/
Summaries are generated and may contain mistakes; the official description above is the record.