# CVE-2024-21609: Denial of service in Junos OS

> An adjacent attacker can cause a denial of service in Junos OS by triggering a memory leak in the IKE daemon during IPsec rekeying.

- **Severity:** High 7.1 (`CVSS:4.0/AV:A/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:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Apr 2024
- **Updated:** 1 Aug 2024
- **Also known as:** GHSA-rh3c-7xc7-jjwj

## What is CVE-2024-21609?

CVE-2024-21609 is a high-severity denial of service vulnerability in Juniper Junos, published on 12 Apr 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 IKE daemon (iked) of Juniper Networks Junos OS on MX Series with SPC3, and SRX Series allows an administratively adjacent attacker which is able to successfully establish IPsec tunnels to cause a Denial of Service (DoS).

If specific values for the IPsec parameters local-ip, remote-ip, remote ike-id, and traffic selectors are sent from the peer, a memory leak occurs during every IPsec SA rekey which is carried out with a specific message sequence. This will eventually result in an iked process crash and restart.

The iked process memory consumption can be checked using the below command:
  user@host> show system processes extensive | grep iked
           PID   USERNAME     PRI  NICE    SIZE    RES    STATE    C   TIME  WCPU COMMAND
           56903 root         31    0      4016M  2543M   CPU0     0   2:10  10.50% iked

This issue affects Juniper Networks Junos OS:
  *  All versions earlier than 20.4R3-S9;
  *  21.2 versions earlier than 21.2R3-S7;
  *  21.3 versions earlier than 21.3R3-S5;
  *  21.4 versions earlier than 21.4R3-S4;
  *  22.1 versions earlier than 22.1R3-S3;
  *  22.2 versions earlier than 22.2R3-S2;
  *  22.3 versions earlier than 22.3R3;
  *  22.4 versions earlier than 22.4R3;
  *  23.2 versions earlier than 23.2R1-S2, 23.2R2.

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

## Which versions are affected by CVE-2024-21609?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2024-21609?

No fix has been published for CVE-2024-21609 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-21609 being exploited?

There is no known exploitation of CVE-2024-21609 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-2024-21609 and fix it if it is affected.

What it is: CVE-2024-21609 is a high-severity denial of service vulnerability in Juniper Junos, published on 12 Apr 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-2024-21609 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-2024-21609/ (Markdown: https://insights.sbomify.com/CVE-2024-21609/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-21609
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-21609
- OSV: https://osv.dev/vulnerability/CVE-2024-21609

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-21609/
Summaries are generated and may contain mistakes; the official description above is the record.