# CVE-2023-4481: Denial of service in Junos OS

> Remote attackers can cause a sustained Denial of Service by sending crafted BGP UPDATE messages to Juniper Junos OS devices.

- **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:** 31 Aug 2023
- **Updated:** 2 Oct 2024
- **Also known as:** GHSA-559g-r8hh-jrx5

## What is CVE-2023-4481?

CVE-2023-4481 is a high-severity denial of service vulnerability in Juniper Junos, published on 31 Aug 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

When certain specific crafted BGP UPDATE messages are received over an established BGP session, one BGP session may be torn down with an UPDATE message error, or the issue may propagate beyond the local system which will remain non-impacted, but may affect one or more remote systems. This issue is exploitable remotely as the crafted UPDATE message can propagate through unaffected systems and intermediate BGP speakers.
Continuous receipt of the crafted BGP UPDATE messages will create a sustained Denial of Service (DoS) condition for impacted devices.

This issue affects eBGP and iBGP, in both IPv4 and IPv6 implementations.  This issue requires a remote attacker to have at least one established BGP session.
 Improper Input Validation, Denial of Service vulnerability in Juniper Networks, Inc. Junos OS (BGP, rpd modules), Juniper Networks, Inc. Junos OS Evolved (BGP, rpd modules) allows Fuzzing.This issue affects 

Junos OS: 

  *  All versions before 20.4R3-S10,
  *  from 21.1R1 through 21.*,
  *  from 21.2 before 21.2R3-S5,
  *  from 21.3 before 21.3R3-S5,
  *  from 21.4 before 21.4R3-S7 (unaffected from 21.4R3-S5, affected from 21.4R3-S6)
  *  from 22.1 before 22.1R3-S4,
  *  from 22.2 before 22.2R3-S3,
  *  from 22.3 before 22.3R3-S1,
  *  from 22.4 before 22.4R3,
  *  from 23.2 before 23.2R2.

Junos OS Evolved:

  *  All versions before 20.4R3-S10-EVO,
  *  from 21.2-EVO before 21.2R3-S7-EVO,
  *  from 21.3-EVO before 21.3R3-S5-EVO,
  *  from 21.4-EVO before 21.4R3-S5-EVO,
  *  from 22.1-EVO before 22.1R3-S4-EVO,
  *  from 22.2-EVO before 22.2R3-S3-EVO,
  *  from 22.3-EVO before 22.3R3-S1-EVO,
  *  from 22.4-EVO before 22.4R3-EVO,
  *  from 23.2-EVO before 23.2R2-EVO.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2023-4481?

It affects 2 products.


Products: Juniper Junos, Juniper Junos Os Evolved.

## How do I fix CVE-2023-4481?

No fix has been published for CVE-2023-4481 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-4481 being exploited?

There is no known exploitation of CVE-2023-4481 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-2023-4481 and fix it if it is affected.

What it is: CVE-2023-4481 is a high-severity denial of service vulnerability in Juniper Junos, published on 31 Aug 2023. 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-2023-4481 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-2023-4481/ (Markdown: https://insights.sbomify.com/CVE-2023-4481/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-4481
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-4481
- OSV: https://osv.dev/vulnerability/CVE-2023-4481

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-4481/
Summaries are generated and may contain mistakes; the official description above is the record.