# CVE-2024-21598: Junos OS and Junos OS Evolved: A malformed BGP tunnel encapsulation attribute will lead to an rpd crash

> An unauthenticated attacker can crash the routing daemon by sending a malformed BGP tunnel encapsulation attribute, causing a denial of service.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/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:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Apr 2024
- **Updated:** 1 Aug 2024
- **Also known as:** GHSA-p5h3-wwqf-f5rv

## What is CVE-2024-21598?

CVE-2024-21598 is a high-severity denial of service vulnerability in Juniper Junos, published on 12 Apr 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An Improper Validation of Syntactic Correctness of Input vulnerability in the Routing Protocol Daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows a network-based, unauthenticated attacker to cause a Denial of Service (DoS).

If a BGP update is received over an established BGP session which contains a tunnel encapsulation attribute with a specifically malformed TLV, rpd will crash and restart.

This issue affects Juniper Networks
Junos OS:
  *  20.4 versions 20.4R1 and later 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-S5;
  *  22.1 versions earlier than 22.1R3-S4;
  *  22.2 versions earlier than 22.2R3-S3;
  *  22.3 versions earlier than 22.3R3-S1;
  *  22.4 versions earlier than 22.4R3;
  *  23.2 versions earlier than 23.2R1-S2, 23.2R2;

Junos OS Evolved:
  *  20.4-EVO versions 20.4R1-EVO and later versions earlier than 20.4R3-S9-EVO;
  *  21.2-EVO versions earlier than 21.2R3-S7-EVO;
  *  21.3-EVO versions earlier than 21.3R3-S5-EVO;
  *  21.4-EVO versions earlier than 21.4R3-S5-EVO;
  *  22.1-EVO versions earlier than 22.1R3-S4-EVO;
  *  22.2-EVO versions earlier than 22.2R3-S3-EVO;
  *  22.3-EVO versions earlier than 22.3R3-S1-EVO;
  *  22.4-EVO versions earlier than 22.4R3-EVO;
  *  23.2-EVO versions earlier than 23.2R1-S2-EVO, 23.2R2-EVO;

This issue does not affect Juniper Networks
  *  Junos OS versions earlier than 20.4R1;
  *  Junos OS Evolved versions earlier than 20.4R1-EVO.

This is a related but separate issue than the one described in JSA79095.

Weakness: CWE-1286 (Improper Validation of Syntactic Correctness of Input)

## Which versions are affected by CVE-2024-21598?

It affects 2 products.


Products: Juniper Junos, Juniper Junos Os Evolved.

## How do I fix CVE-2024-21598?

No fix has been published for CVE-2024-21598 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-21598 being exploited?

There is no known exploitation of CVE-2024-21598 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-2024-21598 and fix it if it is affected.

What it is: CVE-2024-21598 is a high-severity denial of service vulnerability in Juniper Junos, published on 12 Apr 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-2024-21598 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-2024-21598/ (Markdown: https://insights.sbomify.com/CVE-2024-21598/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-21598
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-21598
- OSV: https://osv.dev/vulnerability/CVE-2024-21598

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-21598/
Summaries are generated and may contain mistakes; the official description above is the record.