# CVE-2024-39551: Denial of service in Junos OS

> An unauthenticated attacker can cause a denial of service by sending specific H.323 packets to Juniper SRX and MX devices, leading to traffic loss.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 11 Jul 2024
- **Updated:** 2 Aug 2024
- **Also known as:** GHSA-ggg9-6q5p-37j3

## What is CVE-2024-39551?

CVE-2024-39551 is a high-severity denial of service vulnerability in Juniper Junos, published on 11 Jul 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An Uncontrolled Resource Consumption vulnerability in the H.323 ALG (Application Layer Gateway) of  Juniper Networks Junos OS on SRX Series and MX Series with SPC3 and MS-MPC/MIC, allows an unauthenticated network-based attacker to send specific packets causing traffic loss leading to Denial of Service (DoS). 

Continued receipt and processing of these specific packets will sustain the Denial of Service condition.

The memory usage can be monitored using the below command.

  user@host> show usp memory segment sha data objcache jsf 
This issue affects SRX Series and MX Series with SPC3 and MS-MPC/MIC: 

  *   20.4 before 20.4R3-S10, 
  *   21.2 before 21.2R3-S6, 
  *   21.3 before 21.3R3-S5, 
  *   21.4 before 21.4R3-S6, 
  *   22.1 before 22.1R3-S4, 
  *   22.2 before 22.2R3-S2, 
  *   22.3 before 22.3R3-S1, 
  *   22.4 before 22.4R3, 
  *   23.2 before 23.2R2.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2024-39551?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2024-39551?

No fix has been published for CVE-2024-39551 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-39551 being exploited?

There is no known exploitation of CVE-2024-39551 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-2024-39551 and fix it if it is affected.

What it is: CVE-2024-39551 is a high-severity denial of service vulnerability in Juniper Junos, published on 11 Jul 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-39551 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-2024-39551/ (Markdown: https://insights.sbomify.com/CVE-2024-39551/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-39551
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-39551
- OSV: https://osv.dev/vulnerability/CVE-2024-39551

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-39551/
Summaries are generated and may contain mistakes; the official description above is the record.