# CVE-2025-21595: Junos OS and Junos OS Evolved: In an EVPN-VXLAN scenario specific ARP or NDP packets cause FPC to crash

> Adjacent attackers can crash network line cards by sending specific ARP or NDP packets in EVPN-VXLAN environments, causing a denial of service.

- **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:** 9 Apr 2025
- **Updated:** 10 Apr 2025
- **Also known as:** GHSA-7fvw-hrgg-4cr6

## What is CVE-2025-21595?

CVE-2025-21595 is a high-severity denial of service vulnerability in Juniper Junos, published on 9 Apr 2025. 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 Packet Forwarding Engine (PFE) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker to cause an FPC to crash, leading to Denial of Service (DoS).

On all Junos OS and Junos OS Evolved platforms, in an EVPN-VXLAN scenario, when specific ARP packets are received on an IPv4 network, or specific NDP packets are received on an IPv6 network, kernel heap memory leaks, which eventually leads to an FPC crash and restart.

This issue does not affect MX Series platforms.
Heap size growth on FPC can be seen using below command.

user@host> show chassis fpc
                    Temp CPU Utilization (%) CPU Utilization (%) Memory   Utilization (%)
Slot State           (C) Total Interrupt     1min   5min   15min   DRAM (MB)   Heap   Buffer
  0 Online           45     3         0       2       2      2       32768      19       0 <<<<<<< Heap increase in all fPCs

This issue affects Junos OS:

  *  All versions before 21.2R3-S7,
  *  21.4 versions before 21.4R3-S4,
  *  22.2 versions before 22.2R3-S1, 
  *  22.3 versions before 22.3R3-S1, 
  *  22.4 versions before 22.4R2-S2, 22.4R3.

and Junos OS Evolved:

  *  All versions before 21.2R3-S7-EVO,
  *  21.4-EVO versions before 21.4R3-S4-EVO,
  *  22.2-EVO versions before 22.2R3-S1-EVO, 
  *  22.3-EVO versions before 22.3R3-S1-EVO, 

  *  22.4-EVO versions before 22.4R3-EVO.

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

## Which versions are affected by CVE-2025-21595?

It affects 2 products.


Products: Juniper Junos, Juniper Junos Os Evolved.

## How do I fix CVE-2025-21595?

No fix has been published for CVE-2025-21595 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-21595 being exploited?

There is no known exploitation of CVE-2025-21595 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-2025-21595 and fix it if it is affected.

What it is: CVE-2025-21595 is a high-severity denial of service vulnerability in Juniper Junos, published on 9 Apr 2025. 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-2025-21595 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-2025-21595/ (Markdown: https://insights.sbomify.com/CVE-2025-21595/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-21595
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-21595
- OSV: https://osv.dev/vulnerability/CVE-2025-21595

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-21595/
Summaries are generated and may contain mistakes; the official description above is the record.