# CVE-2024-39518: Memory corruption in Junos OS

> A heap-based buffer overflow in Junos OS telemetry sensor causes memory leaks and device unresponsiveness when specific subscriptions are active.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/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:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Jul 2024
- **Updated:** 2 Aug 2024
- **Also known as:** GHSA-9j54-8gmh-m2jr

## What is CVE-2024-39518?

CVE-2024-39518 is a high-severity memory corruption 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 Heap-based Buffer Overflow vulnerability in the telemetry sensor process (sensord) of Juniper Networks Junos OS on MX240, MX480, MX960 platforms using MPC10E causes a steady increase in memory utilization, ultimately leading to a Denial of Service (DoS).

When the device is subscribed to a specific subscription on Junos Telemetry Interface, a slow memory leak occurs and eventually all resources are consumed and the device becomes unresponsive. A manual reboot of the Line Card will be required to restore the device to its normal functioning. 

This issue is only seen when telemetry subscription is active.

The Heap memory utilization can be monitored using the following command:
  > show system processes extensive

The following command can be used to monitor the memory utilization of the specific sensor
  > show system info | match sensord
   PID   NAME                 MEMORY     PEAK MEMORY    %CPU   THREAD-COUNT CORE-AFFINITY   UPTIME

   1986  sensord            877.57MB   877.57MB         2       4           0,2-15          7-21:41:32

This issue affects Junos OS: 

  *  from 21.2R3-S5 before 21.2R3-S7, 
  *  from 21.4R3-S4 before 21.4R3-S6, 
  *  from 22.2R3 before 22.2R3-S4, 
  *  from 22.3R2 before 22.3R3-S2, 
  *  from 22.4R1 before 22.4R3, 
  *  from 23.2R1 before 23.2R2.

Weakness: CWE-787 (Out-of-bounds Write), CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2024-39518?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2024-39518?

No fix has been published for CVE-2024-39518 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-39518 being exploited?

There is no known exploitation of CVE-2024-39518 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-2024-39518 and fix it if it is affected.

What it is: CVE-2024-39518 is a high-severity memory corruption 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-2024-39518 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-2024-39518/ (Markdown: https://insights.sbomify.com/CVE-2024-39518/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-39518
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-39518
- OSV: https://osv.dev/vulnerability/CVE-2024-39518

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-39518/
Summaries are generated and may contain mistakes; the official description above is the record.