# CVE-2024-39554: Junos OS and Junos OS Evolved: BGP multipath incremental calculation is resulting in an rpd crash

> An unauthenticated attacker can cause a denial of service by triggering a race condition in the routing daemon when BGP multipath is enabled.

- **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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Jul 2024
- **Updated:** 2 Aug 2024
- **Also known as:** GHSA-9fwf-h53q-xxw3

## What is CVE-2024-39554?

CVE-2024-39554 is a high-severity vulnerability in Juniper Junos, published on 10 Jul 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability the 

Routing Protocol Daemon (rpd)

 of Juniper Networks Junos OS and Juniper Networks Junos OS Evolved allows an unauthenticated, network-based attacker to inject incremental routing updates when BGP multipath is enabled, causing rpd to crash and restart, resulting in a Denial of Service (DoS). Since this is a timing issue (race condition), the successful exploitation of this vulnerability is outside the attacker's control.  However, continued receipt and processing of this packet may create a sustained Denial of Service (DoS) condition.

On all Junos OS and Junos OS Evolved platforms with BGP multipath enabled, a specific multipath calculation removes the original next hop from the multipath lead routes nexthop-set. When this change happens, multipath relies on certain internal timing to record the update.  Under certain circumstance and with specific timing, this could result in an rpd crash.

This issue only affects systems with BGP multipath enabled.

This issue affects:

Junos OS: 

  *  All versions of 21.1
  *  from 21.2 before 21.2R3-S7, 
  *  from 21.4 before 21.4R3-S6, 
  *  from 22.1 before 22.1R3-S5, 
  *  from 22.2 before 22.2R3-S3, 
  *  from 22.3 before 22.3R3-S2, 
  *  from 22.4 before 22.4R3, 
  *  from 23.2 before 23.2R2.

Junos OS Evolved: 

  *  All versions of 21.1-EVO,
  *  All versions of 21.2-EVO,
  *  from 21.4-EVO before 21.4R3-S6-EVO, 
  *  from 22.1-EVO before 22.1R3-S5-EVO, 
  *  from 22.2-EVO before 22.2R3-S3-EVO, 
  *  from 22.3-EVO before 22.3R3-S2-EVO, 
  *  from 22.4-EVO before 22.4R3-EVO, 
  *  from 23.2-EVO before 23.2R2-EVO.

Versions of Junos OS before 21.1R1 are unaffected by this vulnerability.
Versions of Junos OS Evolved before 21.1R1-EVO are unaffected by this vulnerability.

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2024-39554?

It affects 2 products.


Products: Juniper Junos, Juniper Junos Os Evolved.

## How do I fix CVE-2024-39554?

No fix has been published for CVE-2024-39554 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-39554 being exploited?

There is no known exploitation of CVE-2024-39554 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-2024-39554 and fix it if it is affected.

What it is: CVE-2024-39554 is a high-severity vulnerability in Juniper Junos, published on 10 Jul 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-2024-39554 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-2024-39554/ (Markdown: https://insights.sbomify.com/CVE-2024-39554/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-39554
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-39554
- OSV: https://osv.dev/vulnerability/CVE-2024-39554

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-39554/
Summaries are generated and may contain mistakes; the official description above is the record.