# CVE-2023-36848: Junos OS: MX Series: The FPC will crash on receiving a malformed CFM packet

> An unauthenticated adjacent attacker can cause a sustained denial of service on Juniper MX Series devices by sending malformed CFM packets if CFM is configured.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:A/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:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Jul 2023
- **Updated:** 22 Oct 2024
- **Also known as:** GHSA-pv7q-j2wh-2hh7

## What is CVE-2023-36848?

CVE-2023-36848 is a medium-severity denial of service vulnerability in Juniper Junos, published on 14 Jul 2023. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An Improper Handling of Undefined Values vulnerability in the periodic packet management daemon (PPMD) of Juniper Networks Junos OS on MX Series(except MPC10, MPC11 and LC9600) allows an unauthenticated adjacent attacker to cause a Denial of Service (DoS).

When a malformed CFM packet is received, it leads to an FPC crash. Continued receipt of these packets causes a sustained denial of service. This vulnerability occurs only when CFM has been configured on the interface.

This issue affects Juniper Networks Junos OS:
versions prior to 19.1R3-S10 on MX Series;
19.2 versions prior to 19.2R3-S7 on MX Series;
19.3 versions prior to 19.3R3-S8 on MX Series;
19.4 versions prior to 19.4R3-S12 on MX Series;
20.1 version 20.1R1 and later versions on MX Series;
20.2 versions prior to 20.2R3-S8 on MX Series;
20.3 version 20.3R1 and later versions on MX Series;
20.4 versions prior to 20.4R3-S7  on MX Series;
21.1 versions prior to 21.1R3-S5 on MX Series;
21.2 versions prior to 21.2R3-S5 on MX Series;
21.3 versions prior to 21.3R3-S4 on MX Series;
21.4 versions prior to 21.4R3-S4 on MX Series;
22.1 versions prior to 22.1R3-S3 on MX Series;
22.2 versions prior to 22.2R3-S1 on MX Series;
22.3 versions prior to 22.3R3 on MX Series;
22.4 versions prior to 22.4R1-S2, 22.4R2 on MX Series.

Weakness: CWE-232 (Improper Handling of Undefined Values)

## Which versions are affected by CVE-2023-36848?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2023-36848?

No fix has been published for CVE-2023-36848 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-36848 being exploited?

There is no known exploitation of CVE-2023-36848 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-2023-36848 and fix it if it is affected.

What it is: CVE-2023-36848 is a medium-severity denial of service vulnerability in Juniper Junos, published on 14 Jul 2023. 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-2023-36848 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-2023-36848/ (Markdown: https://insights.sbomify.com/CVE-2023-36848/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-36848
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-36848
- OSV: https://osv.dev/vulnerability/CVE-2023-36848

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-36848/
Summaries are generated and may contain mistakes; the official description above is the record.