# CVE-2025-21598: Denial of service in Junos OS

> An unauthenticated attacker can crash the routing daemon by sending malformed BGP packets to devices with traceoptions enabled, causing denial of service.

- **Severity:** High 8.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/V:C/RE:M/U:Amber`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Jan 2025
- **Updated:** 9 Jan 2025
- **Also known as:** GHSA-68jp-4r95-v8vr

## What is CVE-2025-21598?

CVE-2025-21598 is a high-severity denial of service vulnerability in Juniper Junos, published on 9 Jan 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An Out-of-bounds Read vulnerability in Juniper Networks Junos OS and Junos OS Evolved's routing protocol daemon (rpd) allows an unauthenticated, network-based attacker to send malformed BGP packets to a device configured with packet receive trace options enabled to crash rpd.
This issue affects:

Junos OS: 

  *  from 21.2R3-S8 before 21.2R3-S9, 
  *  from 21.4R3-S7 before 21.4R3-S9, 
  *  from 22.2R3-S4 before 22.2R3-S5, 
  *  from 22.3R3-S2 before 22.3R3-S4, 
  *  from 22.4R3 before 22.4R3-S5, 
  *  from 23.2R2 before 23.2R2-S2, 
  *  from 23.4R1 before 23.4R2-S1, 
  *  from 24.2R1 before 24.2R1-S1, 24.2R2.

Junos OS Evolved:
  *  from 21.4R3-S7-EVO before 21.4R3-S9-EVO, 
  *  from 22.2R3-S4-EVO before 22.2R3-S5-EVO, 
  *  from 22.3R3-S2-EVO before 22.3R3-S4-EVO, 
  *  from 22.4R3-EVO before 22.4R3-S5-EVO, 
  *  from 23.2R2-EVO before 23.2R2-S2-EVO, 
  *  from 23.4R1-EVO before 23.4R2-S1-EVO, 
  *  from 24.2R1-EVO before 24.2R1-S2-EVO, 24.2R2-EVO.

This issue requires a BGP session to be established.

This issue can propagate and multiply through multiple ASes until reaching vulnerable devices.

This issue affects iBGP and eBGP.

This issue affects IPv4 and IPv6.

An indicator of compromise may be the presence of malformed update messages in a neighboring AS which is unaffected by this issue:

For example, by issuing the command on the neighboring device:
 show log messages

Reviewing for similar messages from devices within proximity to each other may indicate this malformed packet is propagating:
  rpd[<pid>]: Received malformed update from <IP address> (External AS <AS#>)
and
  rpd[<pid>]: Malformed Attribute

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2025-21598?

It affects 2 products.


Products: Juniper Junos, Juniper Junos Os Evolved.

## How do I fix CVE-2025-21598?

No fix has been published for CVE-2025-21598 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-21598 being exploited?

There is no known exploitation of CVE-2025-21598 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-2025-21598 and fix it if it is affected.

What it is: CVE-2025-21598 is a high-severity denial of service vulnerability in Juniper Junos, published on 9 Jan 2025. 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-2025-21598 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-2025-21598/ (Markdown: https://insights.sbomify.com/CVE-2025-21598/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-21598
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-21598
- OSV: https://osv.dev/vulnerability/CVE-2025-21598

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-21598/
Summaries are generated and may contain mistakes; the official description above is the record.