# CVE-2020-1646: Junos OS and Junos OS Evolved: RPD crash while processing a specific BGP update information.

> A remote attacker can cause a denial of service by sending a specific BGP update to a Juniper network device, crashing the routing process.

- **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:** 17 Jul 2020
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-3vf8-2x93-3hff

## What is CVE-2020-1646?

CVE-2020-1646 is a high-severity denial of service vulnerability in Juniper Junos, published on 17 Jul 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

On Juniper Networks Junos OS and Junos OS Evolved devices, processing a specific UPDATE for an EBGP peer can lead to a routing process daemon (RPD) crash and restart. This issue occurs only when the device is receiving and processing the BGP UPDATE for an EBGP peer. This issue does not occur when the device is receiving and processing the BGP UPDATE for an IBGP peer. However, the offending BGP UPDATE can originally come from an EBGP peer, propagates through the network via IBGP peers without causing crash, then it causes RPD crash when it is processed for a BGP UPDATE towards an EBGP peer. Repeated receipt and processing of the same specific BGP UPDATE can result in an extended Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS: 17.3R3-S6, 17.4R2-S7, and 18.1R3-S7. Juniper Networks Junos OS Evolved 19.2R2-EVO and later versions, prior to 19.3R1-EVO. Other Junos OS releases are not affected.

Weakness: CWE-159 (Improper Handling of Invalid Use of Special Elements)

## Which versions are affected by CVE-2020-1646?

It affects 2 products.


Products: Juniper Junos, Juniper Junos Os Evolved.

## How do I fix CVE-2020-1646?

No fix has been published for CVE-2020-1646 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-1646 being exploited?

There is no known exploitation of CVE-2020-1646 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-2020-1646 and fix it if it is affected.

What it is: CVE-2020-1646 is a high-severity denial of service vulnerability in Juniper Junos, published on 17 Jul 2020. 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-2020-1646 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-2020-1646/ (Markdown: https://insights.sbomify.com/CVE-2020-1646/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-1646
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-1646
- OSV: https://osv.dev/vulnerability/CVE-2020-1646

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-1646/
Summaries are generated and may contain mistakes; the official description above is the record.