# CVE-2024-21611: Denial of service in Junos OS

> An unauthenticated attacker can cause a routing daemon crash via memory leak in jflow scenarios, requiring an upgrade to fix.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/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:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Jan 2024
- **Updated:** 17 Jun 2025
- **Also known as:** GHSA-gpx7-7c62-m3g8

## What is CVE-2024-21611?

CVE-2024-21611 is a high-severity denial of service vulnerability in Juniper Junos, published on 12 Jan 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A Missing Release of Memory after Effective Lifetime vulnerability in the Routing Protocol Daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, network-based attacker to cause a Denial of Service (DoS).

In a Juniper Flow Monitoring (jflow) scenario route churn that causes BGP next hops to be updated will cause a slow memory leak and eventually a crash and restart of rpd.

Thread level memory utilization for the areas where the leak occurs can be checked using the below command:

user@host> show task memory detail | match so_in
so_in6 28 32 344450 11022400 344760 11032320
so_in 8 16 1841629 29466064 1841734 29467744
This issue affects:

Junos OS

  *  21.4 versions earlier than 21.4R3;
  *  22.1 versions earlier than 22.1R3;
  *  22.2 versions earlier than 22.2R3.

Junos OS Evolved

  *  21.4-EVO versions earlier than 21.4R3-EVO;
  *  22.1-EVO versions earlier than 22.1R3-EVO;
  *  22.2-EVO versions earlier than 22.2R3-EVO.

This issue does not affect:

Juniper Networks Junos OS versions earlier than 21.4R1.

Juniper Networks Junos OS Evolved versions earlier than 21.4R1.

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

## Which versions are affected by CVE-2024-21611?

It affects 2 products.


Products: Juniper Junos, Juniper Junos Os Evolved.

## How do I fix CVE-2024-21611?

No fix has been published for CVE-2024-21611 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-21611 being exploited?

There is no known exploitation of CVE-2024-21611 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-2024-21611 and fix it if it is affected.

What it is: CVE-2024-21611 is a high-severity denial of service vulnerability in Juniper Junos, published on 12 Jan 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-2024-21611 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-2024-21611/ (Markdown: https://insights.sbomify.com/CVE-2024-21611/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-21611
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-21611
- OSV: https://osv.dev/vulnerability/CVE-2024-21611

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-21611/
Summaries are generated and may contain mistakes; the official description above is the record.