# CVE-2024-21602: Null dereference in Junos OS Evolved

> An unauthenticated attacker can cause a denial of service on Juniper ACX routers by sending specific IPv4 UDP packets that trigger a null pointer dereference.

- **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-jjrx-x936-xwh4

## What is CVE-2024-21602?

CVE-2024-21602 is a high-severity vulnerability in Juniper Junos Os Evolved, 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 NULL Pointer Dereference vulnerability in Juniper Networks Junos OS Evolved on ACX7024, ACX7100-32C and ACX7100-48L allows an unauthenticated, network-based attacker to cause a Denial of Service (DoS).

If a specific IPv4 UDP packet is received and sent to the Routing Engine (RE) packetio crashes and restarts which causes a momentary traffic interruption. Continued receipt of such packets will lead to a sustained DoS.

This issue does not happen with IPv6 packets.

This issue affects Juniper Networks Junos OS Evolved on ACX7024, ACX7100-32C and ACX7100-48L:

  *  21.4-EVO versions earlier than 21.4R3-S6-EVO;
  *  22.1-EVO versions earlier than 22.1R3-S5-EVO;
  *  22.2-EVO versions earlier than 22.2R2-S1-EVO, 22.2R3-EVO;
  *  22.3-EVO versions earlier than 22.3R2-EVO.

This issue does not affect Juniper Networks Junos OS Evolved versions earlier than 21.4R1-EVO.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2024-21602?

It affects 1 product.


Products: Juniper Junos Os Evolved.

## How do I fix CVE-2024-21602?

No fix has been published for CVE-2024-21602 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-21602 being exploited?

There is no known exploitation of CVE-2024-21602 in the wild and no public exploit code.

## Other vulnerabilities in Juniper Junos Os Evolved

- [CVE-2026-21902](https://insights.sbomify.com/CVE-2026-21902/): Junos OS Evolved: PTX Series: A vulnerability allows a unauthenticated, network-based attacker to execute code as root (critical 9.3)
- [CVE-2023-28983](https://insights.sbomify.com/CVE-2023-28983/): Junos OS Evolved: Shell Injection vulnerability in the gNOI server (high 8.8)
- [CVE-2025-21599](https://insights.sbomify.com/CVE-2025-21599/): Denial of service in Junos OS Evolved (high 8.7)
- [CVE-2024-47502](https://insights.sbomify.com/CVE-2024-47502/): Junos OS Evolved: TCP session state is not always cleared on the Routing Engine leading to DoS (high 8.7)
- [CVE-2024-39531](https://insights.sbomify.com/CVE-2024-39531/): Junos OS Evolved: ACX 7000 Series: Protocol specific DDoS configuration affects other protocols (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-21602 and fix it if it is affected.

What it is: CVE-2024-21602 is a high-severity vulnerability in Juniper Junos Os Evolved, 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-2024-21602 in the wild and no public exploit code.

Affected product: Juniper Junos Os Evolved. 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-2024-21602/ (Markdown: https://insights.sbomify.com/CVE-2024-21602/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-21602
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-21602
- OSV: https://osv.dev/vulnerability/CVE-2024-21602

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-21602/
Summaries are generated and may contain mistakes; the official description above is the record.