# CVE-2023-36836: Denial of service in Junos OS

> A local authenticated attacker can cause a routing daemon crash and denial of service in a specific MoFRR configuration scenario.

- **Severity:** Medium 4.7 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **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-jmpv-5c86-5fj9

## What is CVE-2023-36836?

CVE-2023-36836 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

A Use of an Uninitialized Resource vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows a local, authenticated attacker with low privileges to cause a Denial of Service (DoS).

On all Junos OS and Junos OS Evolved platforms, in a Multicast only Fast Reroute (MoFRR) scenario, the rpd process can crash when a a specific low privileged CLI command is executed. The rpd crash will impact all routing protocols until the process has automatically been restarted. As the operational state which makes this issue exploitable is outside the attackers control, this issue is considered difficult to exploit. Continued execution of this command will lead to a sustained DoS.

This issue affects:
Juniper Networks Junos OS
19.4 version 19.4R3-S5 and later versions prior to 19.4R3-S9;
20.1 version 20.1R2 and later versions;
20.2 versions prior to 20.2R3-S7;
20.3 versions prior to 20.3R3-S5;
20.4 versions prior to 20.4R3-S6;
21.1 versions prior to 21.1R3-S4;
21.2 versions prior to 21.2R3-S2;
21.3 versions prior to 21.3R3-S1;
21.4 versions prior to 21.4R3;
22.1 versions prior to 22.1R1-S2, 22.1R2;
22.2 versions prior to 22.2R2.

Juniper Networks Junos OS Evolved
All versions prior to 20.4R3-S6-EVO;
21.1-EVO version 21.1R1-EVO and later versions;
21.2-EVO version 21.2R1-EVO and later versions;
21.3-EVO versions prior to 21.3R3-S1-EVO;
21.4-EVO versions prior to 21.4R3-EVO;
22.1-EVO versions prior to 22.1R1-S2-EVO, 22.1R2-EVO;
22.2-EVO versions prior to 22.2R2-EVO.

Weakness: CWE-908 (Use of Uninitialized Resource)

## Which versions are affected by CVE-2023-36836?

It affects 2 products.


Products: Juniper Junos, Juniper Junos Os Evolved.

## How do I fix CVE-2023-36836?

No fix has been published for CVE-2023-36836 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-36836 being exploited?

There is no known exploitation of CVE-2023-36836 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-2023-36836 and fix it if it is affected.

What it is: CVE-2023-36836 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-2023-36836 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-2023-36836/ (Markdown: https://insights.sbomify.com/CVE-2023-36836/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-36836
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-36836
- OSV: https://osv.dev/vulnerability/CVE-2023-36836

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-36836/
Summaries are generated and may contain mistakes; the official description above is the record.