# CVE-2024-21599: Junos OS: MX Series: MPC3E memory leak with PTP configuration

> An adjacent attacker can cause a denial of service on Juniper MX Series routers by sending PTP packets to unsupported MPC3E cards, triggering a memory leak.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Jan 2024
- **Updated:** 16 Jun 2025
- **Also known as:** GHSA-pw7f-949h-594r

## What is CVE-2024-21599?

CVE-2024-21599 is a medium-severity denial of service vulnerability in Juniper Junos, published on 12 Jan 2024. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A Missing Release of Memory after Effective Lifetime vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX Series allows an adjacent, unauthenticated attacker to cause a Denial of Service (DoS).

If an MX Series device receives PTP packets on an MPC3E that doesn't support PTP this causes a memory leak which will result in unpredictable behavior and ultimately in an MPC crash and restart.

To monitor for this issue, please use the following FPC vty level commands:

show heap
shows an increase in "LAN buffer" utilization and

show clksync ptp nbr-upd-info
shows non-zero "Pending PFEs" counter.

This issue affects Juniper Networks Junos OS on MX Series with MPC3E:

  *  All versions earlier than 20.4R3-S3;
  *  21.1 versions earlier than 21.1R3-S4;
  *  21.2 versions earlier than 21.2R3;
  *  21.3 versions earlier than 21.3R2-S1, 21.3R3;
  *  21.4 versions earlier than 21.4R2;
  *  22.1 versions earlier than 22.1R2.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2024-21599?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2024-21599?

No fix has been published for CVE-2024-21599 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-21599 being exploited?

There is no known exploitation of CVE-2024-21599 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-2024-21599 and fix it if it is affected.

What it is: CVE-2024-21599 is a medium-severity denial of service vulnerability in Juniper Junos, published on 12 Jan 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-2024-21599 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-2024-21599/ (Markdown: https://insights.sbomify.com/CVE-2024-21599/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-21599
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-21599
- OSV: https://osv.dev/vulnerability/CVE-2024-21599

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-21599/
Summaries are generated and may contain mistakes; the official description above is the record.