# CVE-2024-21617: Junos OS: BGP flap on NSR-enabled devices causes memory leak

> An adjacent attacker can cause a memory leak and denial of service on Junos OS devices with Nonstop Routing enabled via BGP flaps.

- **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:** 17 Jun 2025
- **Also known as:** GHSA-mmpf-h3x8-v558

## What is CVE-2024-21617?

CVE-2024-21617 is a medium-severity memory corruption 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

An Incomplete Cleanup vulnerability in Nonstop active routing (NSR) component of Juniper Networks Junos OS allows an adjacent, unauthenticated attacker to cause memory leak leading to Denial of Service (DoS).

On all Junos OS platforms, when NSR is enabled, a BGP flap will cause memory leak. A manual reboot of the system will restore the services.

Note: NSR is not supported on the SRX Series and is therefore not affected by this vulnerability.
The memory usage can be monitored using the below commands.

user@host> show chassis routing-engine no-forwarding
user@host> show system memory | no-more
This issue affects:

Juniper Networks Junos OS

  *  21.2 versions earlier than 21.2R3-S5;
  *  21.3 versions earlier than 21.3R3-S4;
  *  21.4 versions earlier than 21.4R3-S4;
  *  22.1 versions earlier than 22.1R3-S2;
  *  22.2 versions earlier than 22.2R3-S2;
  *  22.3 versions earlier than 22.3R2-S1, 22.3R3;
  *  22.4 versions earlier than 22.4R1-S2, 22.4R2.

This issue does not affect Junos OS versions earlier than 20.4R3-S7.

Weakness: CWE-459 (Incomplete Cleanup)

## Which versions are affected by CVE-2024-21617?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2024-21617?

No fix has been published for CVE-2024-21617 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-21617 being exploited?

There is no known exploitation of CVE-2024-21617 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-2024-21617 and fix it if it is affected.

What it is: CVE-2024-21617 is a medium-severity memory corruption 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-2024-21617 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-2024-21617/ (Markdown: https://insights.sbomify.com/CVE-2024-21617/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-21617
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-21617
- OSV: https://osv.dev/vulnerability/CVE-2024-21617

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-21617/
Summaries are generated and may contain mistakes; the official description above is the record.